Launch Window Planner for Kerbal Space Program
On September 26, 2022, NASA’s Double Asteroid Redirection Test (DART) spacecraft crashed into a binary asteroid system. By intentionally ramming a probe into the 160-meter-wide moonlet named Dimorphos, the smaller of the two asteroids, humanity demonstrated that the kinetic impact method of planetary defense actually works. The immediate result was that Dimorphos’ orbital period around Didymos, its larger parent body, was slashed by 33 minutes.
Of course, altering a moonlet’s local orbit doesn’t seem like enough to safeguard Earth from civilization-ending impacts. But now, as long-term observational data has come in, it seems we accomplished more than that. DART actually changed the trajectory of the entire Didymos binary system, altering its orbit around the Sun. //
Because Dimorphos orbits Didymos, some of the ejecta remained trapped in the system, where it altered the mutual orbit between the two rocks. But a crucial fraction of the ejecta achieved escape velocity from the entire binary system. The momentum carried away by the system-escaping debris is what ultimately contributed to shoving the center of mass of the whole Didymos-Dimorphos pair. “In our case, we found that the beta parameter due to DART impact was around two,” Makadia explained.
The debris blasted completely out of the Didymos system gave the asteroids a push roughly equal to the initial impact of the spacecraft itself. //
The goal of DART was primarily to take our planetary defense out of the realm of computer models and get us some hands-on, practical experience, and Makadia thinks we succeeded in doing that. “Our work proves that hitting the secondary asteroid is a viable path for deflecting a binary system away as long as the push is large enough,” he said. “This wasn’t the goal of DART, but we can always design a bigger spacecraft.”
Statistical Ars Legatus Legionis
15y
54,490
pseudonomous said:
I will presume that both you and the NASA guys got the math right and that for a polar landing NRHO makes sense. But if they are really going to "question all requirements", we have to admit the possibility that they might fly Artemis IV or V as an equatorial region landing, do we not?
For Orion as a crew vehicle it doesn't matter. Orion has 1,300 m/s of DeltaV of which 300 m/s is allocated for docking, station keeping, and course corrections. So it is limited to orbits which require <1000 m/s to enter AND exit (NRHO is about 900 m/s). Even equatorial LLO with a 3.5 day loiter (13 days + surface time for total mission time) is a minimum of 835 m/s * 2= 1670 m/s. Loiters improve the worst case scenario but only make a small impact on the best case ones. Even if you could modify the Centaur V to have 3 day endurance and cryocoolers and use it for part of LOI (which we shouldn't that will end up being a $5B 10 year boondoggle) it has in the ballpark of 500 m/s excess DeltaV so you are likely still short unless you dip into your reserves.
Longer term with a better crew vehicle you might have the option to go to LLO Direct via fast insertion but it still isn't a slam dunk option with reusable landers as your example bring up. If you have reusable crew landers LLO as a staging point is made worse if you change landing locations. There isn't one LLO and as such to move between LLOs you need to do a plane change. The only cost effective way to make a plane change is to burn to a highly elliptical orbit you know like how NRHO is highly elipitcal. Every mission requires more prop, has more boiloff, and when changing landing sites you also pay a plane change tax. One feature of NRHO is due to its high perilune you can reach every spot on the moon with a consistent DeltaV cost. This makes mission planning a lot easier. You could land near Apollo 11 on the 70th anniversary if you wanted to. It is no harder (or easier) from NRHO than the poles or any other landing site.
To be clear these nuanced challenges mostly apply to the staging point for a crewed mission. If you are fine with adding 15+ day loiter time you can drop heavy cargo on the south pole by going LLO quite cheaply. If it is an expendable cargo lander efficiency doesn't really matter because it is a one way trip so Direct LLO without a loiter becomes viable.
The reality though is it is complicated and it depends on exactly what mission, to exactly where, how long you are willing to loiter, is the lander reusable and is it crewed. Another wrinkle is if it is crewed are the crew in their own vehicle or pushed there by the tanker. If the crew is riding on the tanker than fast insertion is required which means your crew made the thousands of tons of prop more expensive as well. Likely to the dismay of people in NASA doing this kind of analysis the public discourse though has largely been "NRHO is stupid derp derp derp".
Ajax81611 Wise, Aged Ars Veteran
5y
166
Subscriptor
NASA missed a huge soft drink sponsorship opportunity here by not naming it the Perfect Elliptical Polar Stable Insertion with Coplanar Line of Apsides.
Regarding NASA’s support for the development of commercial space stations, the bill mandates the following, within specified periods, of passage of the law:
- Within 60 days, publicly release the requirements for commercial space stations in low-Earth orbit
- Within 90 days, release the final “request for proposals” to solicit industry responses
- Within 180 days, enter into contracts with “two or more” commercial providers for such stations
Cruz is trying to inject urgency into NASA as several private companies—including Axiom Space, Blue Origin, Vast, and Voyager—are finalizing designs for space stations. All have expressed a desire for clarity from NASA on how long the space agency would like its astronauts to stay on board, the types of scientific equipment needed, and much more. These are known as “requirements” in NASA parlance.
SPACE JELLYFISH PREDICTOR
NASA shall evaluate the “viability of transferring the ISS to a safe orbital harbor” after retirement. //
The most recent NASA authorization act, passed in 2022, extended the US government’s support for the ISS program until 2030. The amendment tacked onto this year’s bill would not change the timeline for ending operations on the ISS, but it asks NASA to reconsider its decision about what to do with the complex after retirement.
The amendment would direct NASA to “carry out an engineering analysis to evaluate the technical, operational, and logistical viability of transferring the ISS to a safe orbital harbor and storing the ISS in such harbor after the end of the operational low-Earth orbit lifetime of the ISS to preserve the ISS for potential reuse and satisfy the objectives of NASA.” //
In 2024, NASA awarded SpaceX a nearly $1 billion contract to develop a souped-up version of its Dragon spacecraft, which would be equipped with additional thrusters and propellant tanks to provide the impulse required to steer the space station toward a targeted reentry. The deorbit maneuvers will slow the station’s velocity enough for Earth’s gravity to pull it back into the atmosphere. //
Artist’s illustration of SpaceX’s deorbit vehicle, based on the design of the company’s Dragon spacecraft. The modified spacecraft will have 46 Draco thrusters—30 for the deorbit maneuvers and 16 for attitude control. Credit: SpaceX //
The deorbit vehicle needs to slow the station’s speed by about 127 mph (57 meters per second), a tiny fraction of the spacecraft’s orbital velocity of more than 17,000 mph (7.7 kilometers per second). But the station mass is around 450 tons (400 metric tons), equivalent to two freight train locomotives, and measures about the length of a football field. Changing its speed by just 127 mph will consume about 10 tons (9 metric tons) of propellant, according to a NASA analysis released in 2024.
The analysis document shows that NASA considered alternatives to discarding the space station through reentry. One option NASA studied involved moving the station into a higher orbit. At its current altitude, roughly 260 miles (420 kilometers) above the Earth, the ISS would take one to two years to reenter the atmosphere due to aerodynamic drag if reboosts weren’t performed. NASA does not want the space station to make an uncontrolled reentry because of the risk of fatalities, injuries, and property damage from debris reaching the ground.
Boosting the space station’s orbit to somewhere between 400 and 420 miles (640 to 680 kilometers) would require a little more than twice the propellant (18.9 to 22.3 metric tons) needed for deorbit maneuvers, according to NASA’s analysis. At that altitude, without any additional boosts, NASA says the space station would likely remain in orbit for 100 years before succumbing to atmospheric drag and burning up. Going higher still, the space station could be placed in a 1,200-mile-high (2,000-kilometer) orbit, stable for more than 10,000 years, with about 146 tons (133 metric tons) of propellant.
There are two problems with sending the ISS to higher altitudes. One is that it would require the development of new propulsive and tanker vehicles that do not currently exist, according to NASA. //
BobDole11 Ars Centurion
4y
290
I think everyone would love to see the ISS saved for posterity. I would imagine the grand kids of today's generation, when space flight may perhaps be common, visiting and touring a monument ISS and learning how primitive it was (compared to a +50'ish years future) and the bravery of the souls that ventured forth for the expansion of humanity's knowledge, science, exploration, cooperation, and greatness.
I've had those feelings and thoughts myself when viewing Apollo era hardware long ago. Standing by a Saturn 5 dwarfing my 8yr old stature filled me with inspiration to learn about spaceflight, science, and engineering.
But - the ramifications of a collision (or collisions) with space junk yielding 450 tons of more space junk, yielding further collisions and more and smaller junk, and on and on is just too great. The debris at a higher orbit takes too long to deorbit. The thought of our orbitals becoming impassable for centuries is terrifying. //
Veritas super omens Ars Legatus Legionis
13y
26,080
Subscriptor++
What would it take? Based on the history of the SLS I would predict it would take an order of magnitude more money than whatever NASA says and 20 to 30 years longer. There are many laudable goals for space missions, this isn't one of them!. //
fl4Ksh Ars Tribunus Militum
8y
1,518
Subscriptor
NASA is paying SpaceX $2.9B to develop a Starship lunar lander. That work has been ongoing since late 2021 and is scheduled to launch in late 2028.
That lunar lander design could be a pattern for a Starship LEO space station, which would have 1000 cubic meters of pressurized volume (ISS has 913), would support a crew of 10 (ISS supports 7), would be deployed to LEO in a single Starship launch (ISS required 12 years [1999 to 2011] and 35 launches), and would cost ~$10B (ISS cost $150B to build and deploy to LEO and $3B to $4B per year to operate, in today's money). Like the ISS, that Starship LEO space station would use cargo Dragon and crew Dragon spacecraft for resupply of consumables and for crew rotation.
That Starship LEO space station could be built in 36 months and launched in 2030.
jack1983 Smack-Fu Master, in training
12y
93
The Lurker Beneath said:
Do it on a windy day?
There are risks with too high wind speeds as well. High airflow causes static buildup and turbulence. Hydrogen requires very little ignition energy (well below 1mJ at stoichiometric conditions). So even a gust of wind can set off a combustible mixture.
Cryogenic hydrogen is an absolute nightmare to work with.
paulfdietz Ars Scholae Palatinae
7y
1,168
Using hydrogen as the fuel in the first stage was never a good idea. The density is just terrible, making the first stage much larger. Because the first stage is disposed of so quickly, Isp is less important; what's more important is "density impulse" (density x Isp), and LoX/LH2 is inferior to LOX/hydrocarbon by that metric.
Low density also makes the engines more expensive, as more pumping power is needed for a given thrust. //
paulfdietz Ars Scholae Palatinae
7y
1,168
pokrface said:
Right, but the "first stage" of SLS (and STS) is properly the SRBs.
It's more like the first "half stage". What matters for the argument is the velocity at which a stage is done. Even with the SRBs there, that's not that high (although higher than say the Falcon 9, which ends the stage 1 burn at an unusually low velocity so it can be recovered.)
The SRBs do allow the thrust of those LH2 engines to be somewhat lower, since they don't have to lift the fully fueled stack off the pad themselves. By the time the SRBs drop some propellant is gone. This ameliorates to some extent the relatively poor thrust/weight ratio of the engines (73.1 vs 184 for the Merlin 1D.)
The advertisement on the auction website was titled “Space Shuttle Remove Before Flight Flags Lot of 18.” They were listed with an opening bid of $3.99. On January 12, 2010, I paid $5.50 as the winner.
At that point, my interest in the 3-inch-wide by 12-inch-long (7.6 by 30.5 cm) tags was as handouts for kids and other attendees at future events. Whether it was at an astronaut autograph convention, a space memorabilia show, a classroom visit, or a conference talk, having “swag” was a great way to foster interest in space history. At first glance, these flags seemed to be a perfect fit.
So I didn’t pay much attention when they first arrived. The eBay listing had promoted them only as generic examples of “KSC Form 4-226 (6/77)"—the ID the Kennedy Space Center assigned to the tags. //
It was about a year later when I first noticed the ink stamps at the bottom of each tag. They were marked “ET-26” followed by a number. For example, the first tag in the clipped-together stack was stamped “ET-26-000006.” //
A fact sheet prepared by Lockheed Martin provided the answer. The company operated at the Michoud Assembly Facility near New Orleans, where the external tanks were built before being barged to the Kennedy Space Center for launch. Part of the sheet listed each launch with its date and numbered external tank. As my finger traced down the page, it came to STS 61-B, 11/26/85, ET-22; STS 61-C, 1/12/86, ET-30; and then STS 51-L, 1/28/86… ET-26. //
Once the tags’ association with STS-51L was confirmed, it no longer felt right to use them as giveaways. At least, not to individuals.
There are very few items directly connected to Challenger‘s last flight that museums and other public centers can use to connect their visitors to what transpired 40 years ago. NASA has placed only one piece of Challenger on public display, and that is in the exhibition “Forever Remembered” at the Kennedy Space Center Visitor Complex. //
digital.rain Smack-Fu Master, in training
2y
34
Sarty said:
It is such an extremely NASA thing to do to mark items so mundane and interchangeable as remove-before-flight tags with individually traceable serial numbers.
It has to be one of the quality control check points … you know you placed, say, 56 tags for a specific mission. After removal, you can check that all the 56 tags for that mission have been properly removed.
Harrison Schmitt, speaking with a NASA interviewer in 2000, said his productivity in the Apollo suit “couldn’t have been much more than 10 percent of what you would do normally here on Earth.”
“You take the human brain, the human eyes, and the human hands into space. That’s the only justification you have for having human beings in space,” Schmitt said. “It’s a massive justification, but that’s what you want to use, and all three have distinct benefits in productivity and in gathering new information and infusing data over any automated system. Unfortunately, we have discarded one of those, and that is the hands.”
Schmitt singled out the gloves as the “biggest problem” with the Apollo suits. “The gloves are balloons, and they’re made to fit,” he said. Picking something up with a firm grip requires squeezing against the pressure inside the suit. The gloves can also damage astronauts’ fingernails.
“That squeezing against that pressure causes these forearm muscles to fatigue very rapidly,” Schmitt said. “Just imagine squeezing a tennis ball continuously for eight hours or 10 hours, and that’s what you’re talking about.”
Barratt recounted a conversation in which Schmitt, now 90, said he wouldn’t have wanted to do another spacewalk after his three excursions with commander Gene Cernan on Apollo 17.
“Physically, and from a suit-maintenance standpoint, he thought that that was probably the limit, what they did,” Barratt said. “They were embedded with dust. The visors were abraded. Every time they brushed the dust off the visors, they lost visibility.”
Getting the Artemis spacesuit right is vital to the program’s success. You don’t want to travel all the way to the Moon and stop exploring because of sore fingers or an injured knee.
“If you look at what we’re spending on suits versus what we’re spending on the rocket, this is a pretty small amount,” Rubins said. “Obviously, the rocket can kill you very quickly. That needs to be done right. But the continuous improvement in the suit will get us that much more efficiency. Saving 30 minutes or an hour on the Moon, that gives you that much more science.”
“Once you have safely landed on the lunar surface, this is where you’ve got to put your money,” Barratt said.
NASA has never before cut short a human spaceflight mission for medical reasons. “It’s the first time we’ve done a controlled medical evacuation from the vehicle, so that is unusual,” Kshatriya said.
The Soviet Union called an early end for an expedition to the Salyut 7 space station in 1985 after the mission’s commander fell ill in orbit.
In a sense, it is surprising that it took this long. Polk said predictive models suggested the ISS would have a medical evacuation about once every three years. It ended up taking 25 years. In that time, NASA has improved astronauts’ abilities to treat aches and pains, minor injuries, and routine illnesses.
Crews in orbit can now self-treat ailments that might have prompted a crew to return to Earth in the past. One astronaut was diagnosed with deep vein thrombosis, or a blood clot, in 2018 without requiring an early departure from the space station. Another astronaut suffered a pinched nerve in 2021 and remained in orbit for another seven months.
One of the more compelling reasons for the space station’s existence is its ability to act as a testbed for learning how to live and work off the planet. The station has served as a laboratory for studying how spaceflight affects the human body, and as a platform to test life support systems necessary for long-duration voyages to deep space.
FranzJoseph Wise, Aged Ars Veteran
11m
1,581
DavidEmami said:
Hope the everything turns out well for the crew member. It does make me wonder, though -- how would they deal with something life threatening? And have any medical procedures been done in space before? Did some searching and the closest I can find is a post-splashdown injury on Apollo 12 that the crew treated before egress, but that wasn't in free-fall. In particular, I assume the medical concept of the "golden hour" has to be abandoned.
First, obviously IANAD, so take it with a big grain of salt.
"Golden hour" is usually talked in the context of massive traumatic injuries and/or massive haemorrhaging. Even there it's a bit controversial, as it might be more useful only in the context of triage of massively multiple casualties with limited medevac resources down here.
IOTW, if any massive traumatic injury happens on the ISS (say a micrometeorite going through an astronaut or a pressurised cylinder failure resulting in an open fracture and haemorrhaging), the casualty is likely to be fucked anyway.
For things that develop over a longer time (appendicitis ‑‑> septicaemia), the astronauts are hopefully so well monitored that it would be caught early on.
You can find a full equipment list in the CHeCS onboard here (PDF, 2011 link). https://ntrs.nasa.gov/api/citations/20110022379/downloads/20110022379.pdf
Includes BP/ECG, AED, basic dental & surgery stuff (nothing quite major, scalpel and forceps etc), detox kit, airways kit, ambu bag and low‑flow mask and endotracheal oxygen supply, IV with pump and IV solutions, chest drain valve for pneumothorax, dressings, sutures and splints. Plus medicines, obviously.
Not really sure what the survival rate of somebody with a tension pneumothorax would be, even if quickly drained with the drain valve and intubated. I presume NASA has some procedures for getting an intubated or IV'd astronaut back home, even if it might mean not wearing their suit?
What's the max acceleration experienced during re‑entry and chute deployment? Not Soyuz, hopefully something gentler like CrewDragon (I assume Soyuz's retrorockets are less gentle here)?
henryhbk Ars Tribunus Militum
12y
1,891
Subscriptor++
FranzJoseph said:
First, obviously IANAD, so take it with a big grain of salt.
"Golden hour" is usually talked in the context of massive traumatic injuries and/or massive haemorrhaging. Even there it's a bit controversial, as it might be more useful only in the context of triage of massively multiple casualties with limited medevac resources down here.
IOTW, if any massive traumatic injury happens on the ISS (say a micrometeorite going through an astronaut or a pressurised cylinder failure resulting in an open fracture and haemorrhaging), the casualty is likely to be fucked anyway.
For things that develop over a longer time (appendicitis ‑‑> septicaemia), the astronauts are hopefully so well monitored that it would be caught early on.
You can find a full equipment list in the CHeCS onboard here (PDF, 2011 link).
Includes BP/ECG, AED, basic dental & surgery stuff (nothing quite major, scalpel and forceps etc), detox kit, airways kit, ambu bag and low‑flow mask and endotracheal oxygen supply, IV with pump and IV solutions, chest drain valve for pneumothorax, dressings, sutures and splints. Plus medicines, obviously.
Not really sure what the survival rate of somebody with a tension pneumothorax would be, even if quickly drained with the drain valve and intubated. I presume NASA has some procedures for getting an intubated or IV'd astronaut back home, even if it might mean not wearing their suit?
What's the max acceleration experienced during re‑entry and chute deployment? Not Soyuz, hopefully something gentler like CrewDragon (I assume Soyuz's retrorockets are less gentle here)?
Click to expand...
IAAD, most of the survivable emergencies require only a critical but generally simple procedure to buy time. Often I am faced with surgical emergencies in the hospital overnight, and while on paper we have at least one trauma and one cardiac OR on hot standby, it's not like surgeons are standing there in stasis waiting to operate, and often will be several hours until they can formally operate on someone (or we need some test to complete). So for instance for the appendicitis above we use broad spectrum IV antibiotics, then figure it out later, Broken bones easy - splint and transport, pneumothorax (particularly tension) you can do a needle decompression (all it takes is a 20ga IV catheter and a stopcock) and again you've bought plenty of time for surgeons to get ready to do a definitive thoracostomy (chest) tube, most bleeding can be stopped with pressure.
Things where this isn't true would be a stroke or intracranial bleeding. Not 100% sure if the aircraft carriers that picked up Apollo astronauts even have the ability to treat that onboard. depending where the bleed is. If it is an epidural (in the skull, outside the brain but hydraulically crushing the brain) then the answer is simply we drill a hole and relieve the pressure (trepanning) and then some actual neurosurgeon can fix the issue, and when I was the intern, that's who did the burr hole, a 4 minute procedure that bought you hours to the OR. But if the bleed is deeper (such as a sub-arachnoid bleed or interparenchymal bleed) well not much you are doing outside an interventional neuroradiology suite, and those patients often have a poor prognosis on land. Not sure if they screen for berry aneurysms in the astronaut core with a head angiogram? Penetrating trauma management is battlefield medic level care to buy time to get to surgery, and a lot can be done to stall exsanguination within reason without much clinical skill or equipment. There are military medic deployed pro-coagulants that can be put into a wound to form instant clot, and of course the tried and true tampon in the hole. In a penetrating wound something like a tampon works by absorbing blood and expanding to put pressure on the bleeding vessels, which works surprisingly well in the absence of definitive medical care.
As for g-forces anyone who has ridden in an ambulance on our pothole strewn streets in the northeast knows you subject you patient to a surprising number of shock loads, but I worry more about needing to put a critically ill patient into a chair for the descent when bleeding has stopped while lying prone or on their back. Does crew dragon have a stretcher capability?
While Rocketdyne’s ownership merry-go-round kept spinning, the company’s competitors pushed forward. SpaceX and Blue Origin, backed by wealthy owners, took a fresh approach to designing rockets. Apart from the technical innovations that led to reusable rockets, these newer companies emphasized vertical integration to cut costs and minimize reliance on outside supply chains. They wanted to design and build their own rocket engines and were not interested in outsourcing propulsion. Rocketdyne’s business was—and still is—entirely focused on selling ready-made engines to customers.
The launch startups that followed in the footsteps of SpaceX and Blue Origin have largely imitated their approach to insourcing. There are at least nine medium to large liquid-fueled rocket engines in production or in advanced development in the United States today, and just one of them is from the enterprise once known as Rocketdyne: the RS-25 engine used to power the core stage of NASA’s Space Launch System (SLS) rocket. //
The RS-25 engine, by far the largest in L3Harris’ portfolio and a former Rocketdyne product, is not part of the sale. The RS-25 was initially known as the Space Shuttle Main Engine and was designed for reusability. The expendable heavy-lift SLS rocket uses four of the engines, and NASA is burning through the 16 leftover shuttle-era RS-25 engines on the first four SLS flights for the agency’s Artemis Moon program. The second SLS flight is set to launch in the coming months on a mission carrying four astronauts beyond the Moon.
L3Harris will retain total ownership of the RS-25 program. The company has a contract with NASA to build new RS-25 engines for SLS flights beyond Artemis IV. But the new RS-25s will come at an expense of about $100 million per engine, significantly more than SpaceX sells an entire launch on a Falcon 9 rocket. The engine contract is structured as a cost-plus contract, with award and incentive fees paid by the government to L3Harris.
Sending astronauts to the red planet will be a decades-long activity and cost many billions of dollars. So why should NASA undertake such a bold mission?
A new report published Tuesday, titled “A Science Strategy for the Human Exploration of Mars,” represents the answer from leading scientists and engineers in the United States: finding whether life exists, or once did, beyond Earth.
“We’re searching for life on Mars,” said Dava Newman, a professor in the Department of Aeronautics and Astronautics at Massachusetts Institute of Technology and co-chair of the committee that wrote the report, in an interview with Ars. “The answer to the question ‘are we alone‘ is always going to be ‘maybe,’ unless it becomes yes.”
The first multi-spacecraft science mission to launch to Mars is now on its way, and catching a ride on the twin probes are the first kiwis to fly to the red planet. //
“Rocket Lab has a tradition of hiding kiwis in many areas of its design,” said Lindsay McLaurin, senior communications manager for space systems at Rocket Lab, in response to an inquiry from collectSPACE.com. “The birds have snuck onto our rockets and satellites since the beginning of the company, reflecting the New Zealand roots of the company and as a challenge among our designers and spacecraft builders.”
The birds, which are native to the island country in the southwestern Pacific Ocean, appear as graphics on twin plaques attached to Blue and Gold. The metal plates, which adorn one of the two solar panels on each probe, also feature the Rocket Lab logo, the company’s motto (“Non Sufficit Hic Orbis” or “This World Is Not Enough”), and a similar icon of a bald eagle.
“To represent our company’s global presence,” said McLaurin, referring to the American icon. //
GFKBill Ars Tribunus Militum
21y
2,658
Subscriptor
*pushes pedant glasses up nose"
As a Kiwi myself, I need to point out that the Maori language doesn't use the "s" to denote plurals, or even have a letter "s", so it's two kiwi, not two kiwis.
Also, go Rocket Lab!
winwaed Ars Scholae Palatinae
9y
711
GFKBill said:
Maori language doesn't use the "s" to denote plurals, or even have a letter "s", so it's two kiwi, not two kiwis.
So the plural of "sheep" is "heep"?
GFKBill Ars Tribunus Militum
21y
2,658
Subscriptor
winwaed said:
So the plural of "sheep" is "heep"?
Well, we do have heeps of them.
SiberX Ars Scholae Palatinae
15y
1,249
Subscriptor++
GFKBill said:
Well, we do have heeps of them.
We just went over this; heep of them.
My antennae started twitching about Trump and Isaacman on Monday, when space reporter Eric Berger (probably the best in the business) published this story for Ars Technica: Capitol Hill is abuzz with talk of the “Athena” plan for NASA.
Long story short, Athena was Isaacman's plan for cutting costs at NASA and restoring the agency's "mission-first" culture — and getting us back to the Moon, at a price we can afford and before China does. Needless to say, Athena involved upsetting an awful lot of well-anchored apple carts and taking way some gold-plated iron rice bowls.
For starters, Isaacman wants to ditch the stupidly expensive, technological dinosaur knowns as the Space Launch System (SLS), meant to carry Americans back to the Moon. Not only is SLS built from yesterday's disposable rocket parts, but "at $4 billion a launch, you don’t have a Moon program," interim NASA Administrator Sean Duffy (and full-time Transportation Secretary) said back in September. //
Washington read that as "Isaacman is too close to Elon Musk and too far from Lockheed," and that's when the long knives came out for the 42-year-old billionaire and record-setting private astronaut.
AND ANOTHER THING: "Old Space" refers to old-school contractors who have been in the business forever, mostly doing the same things in the same ways — and also to NASA. "New Space" encompasses the free-thinking startups, large and small — and hopefully to NASA under new leadership. //
Cliff_Hanger
a day ago
Thanks for the "ANOTHER THING."
I thought "Old Space" was a cheap knock-off cologne but couldn't figure out what it had to do with NASA.
anon-a-miss Cliff_Hanger
a day ago
It smells almost like "Old Spice", but not quite...
Why settle for Old Space cologne when you can use Musk! //
KS
a day ago
SLS was specified by the Senate to use existing equipment. "Senate Launch System"
The whole point is to spend money on companies that make nice paybacks to politicians.
The reason SpaceX can lauch so cheaply is because they do blow stuff up to find out what works and what doesn't.
If NASA did that, congresscritters would complain "They're wasting taxpayer money! I prefer other ways of wasting taxpayer money!"
I have seen this for 45 years, not just space but FAA. The ATC computer system was seriously obsolete in 1980, but Congress didn't want to allocate money to update it. One big deal to handle the ATC strike was "flow control" - monitoring how busy airspace would be so planes could be held on the ground when there would be delays. The PROTOTYPE was more capable than the deployed system, because Congress insisted the FAA use the obsolete IBM mainframes they bought in the 1960's instead of more modern computers.
(Which is why I think Air Traffic Control should be privatized and paid for by user fees, not funded by Congress. They would be able to make better decisions).
Snowblind KS
a day ago
Which Is crazy as IBM mainframes are transaction monsters. Always have been. But 20 years is a LONG time, 6 or 7 genrations.
I mean sure, the mean time between failures is 25 years.... but that does not mean you should keep them that long! Maintenance goes way up after 2nd Gen has passed, or 6 years. Cost less to replace them.
KS Snowblind
a day ago
These were 360/30's and 40's customized for real-time operation and called 9020's after the Univacs they replaced. By the 1980's, the connectors were suffering metal fatigue.
Both hardware and software had advanced quite a bit and newer more reliable distributed systems were possible.
KS Snowblind
a day ago
Better would be a distributed system. Even replacing the 360's with 370's would have been better, but PDP-10's were quite capable (the flow control prototype I mentioned was written for a PDP-10) and better at real-time work. Although minicomputers such as PDP-11's would do a lot of the I/O.
The problem was, the old mainframes were customized and software would not necessarily run on a newer 360/370 system.
What was done was to somehow get IBM or IBM clones to run the software.
Of course, if this was a government project, we'd still be working on it, and consultants would have made a lot of money.
BTW, back then, I was a subcontractor to DOT from a small company as their cash cow; that company never did make it (technology wasn't ready for a "specification language") but it did have a connection with the space program. HOS - Higher Order Software, started by Margaret Hamilton and Saydean Zeldin (sp?). Look up Margaret Hamilton - did a LOT for the Apollo program. //
polyjunkie
a day ago edited
Elon Musk will greet NASA from his condo on the moon by the time NASA builds a rocket to get there. And his grandchildren will greet NASA on Mars by the time it gets there.
Here’s the way fix NASA: Close it. Make in an Accounts Payable Desk with a list of projects it will pay for:
1) $5B for the first 30 day sojourn on the moon.
2)$2B for an additional 6 months.
3) 25B for the first round trip to Mars with a 30 day stay.
4) $100B for the first 2 year stay on Mars and return for 50 people.
Etc.
Nvidia recently made headlines by announcing that one of the companies it is partnering with, Starcloud, plans to build a 5-gigawatt orbital data center with “super-large solar and cooling panels approximately 4 kilometers in width and length.”
To put that into perspective, the eight main solar arrays on the International Space Station—the largest ever assembled in space, requiring many space shuttle launches and spacewalks—span about 100 meters and produce a maximum of about 240 kW. That’s about 0.005 percent of the power Starcloud intends to generate. //
However, it sounds a little more feasible if such an array could be assembled autonomously. And on Thursday morning, Starcloud, along with a new in-space assembly company, Rendezvous Robotics, announced an agreement to explore the use of modular, autonomous assembly to build Starcloud’s data centers.
A new listing of the 50 most concerning pieces of space debris in low-Earth orbit is dominated by relics more than a quarter-century old, primarily dead rockets left to hurtle through space at the end of their missions. //
Russia and the Soviet Union lead the pack with 34 objects listed in McKnight's Top 50, followed by China with 10, the United States with three, Europe with two, and Japan with one. Russia's SL-16 and SL-8 rockets are the worst offenders, combining to take 30 of the Top 50 slots. //
The list published Friday is an update to a paper authored by McKnight in 2020. This year's list goes a step further by analyzing the overall effect on debris risk if some or all of the worst offenders were removed. If someone sent missions to retrieve all 50 of the objects, the overall debris-generating potential in low-Earth orbit would be reduced by 50 percent, according to McKnight. If just the Top 10 were removed, the risk would be cut by 30 percent. //
China, on the other hand, frequently abandons upper stages in orbit. China launched 21 of the 26 hazardous new rocket bodies over the last 21 months, each averaging more than 4 metric tons (8,800 pounds). Two more came from US launchers, one from Russia, one from India, and one from Iran. //
Since 2000, China has accumulated more dead rocket mass in long-lived orbits than the rest of the world combined, according to McKnight. "But now we're at a point where it's actually kind of accelerating in the last two years as these constellations are getting deployed."
Six decades have now passed since some of the most iconic Project Gemini spaceflights. The 60th anniversary of Gemini 4, when Ed White conducted the first US spacewalk, came in June. The next mission, Gemini 5, ended just two weeks ago, in 1965. These missions are now forgotten by most Americans, as most of the people alive during that time are now deceased.
However, during these early years of spaceflight, NASA engineers and astronauts cut their teeth on a variety of spaceflight firsts, flying a series of harrowing missions during which it seems a miracle that no one died.
Because the Gemini missions, as well as NASA's first human spaceflight program Mercury, yielded such amazing stories, I was thrilled to realize that a new book has recently been published—Gemini & Mercury Remastered—that brings them back to life in vivid color.
The book is a collection of 300 photographs from NASA's Mercury and Gemini programs during the 1960s, in which Andy Saunders has meticulously restored the images and then deeply researched their background to more fully tell the stories behind them. The end result is a beautiful and powerful reminder of just how brave America's first pioneers in space were. What follows is a lightly edited conversation with Saunders about how he developed the book and some of his favorite stories from it.
After nearly half a century in deep space, every ping from Voyager 1 is a bonus
Powered by plutonium, running on pure stubbornness
It is almost half a century since Voyager 1 was launched from Cape Canaveral in Florida on a mission to study Jupiter, Saturn, and the atmosphere of Titan. It continues to send data back to Earth.
Although engineers reckon that the aging spacecraft might survive well into the 2030s before eventually passing out of range of the Deep Space Network, the spacecraft's cosmic ray subsystem was switched off in 2025. More of the probe's instruments are earmarked for termination as engineers eke out Voyager's power supply for a few more years.
On September 5, 1977, the power situation was a good deal healthier when the mission got underway. Launched just over two weeks after Voyager 2, Voyager 1 was scheduled to make flybys of Jupiter and Saturn. It skipped a visit to Pluto in favor of a closer look at the Saturnian moon Titan, which had an intriguing atmosphere.
The launch was the final one for the Titan IIIE rocket and was marred slightly by an earlier-than-expected second stage engine cutoff. NASA averted disaster by using a longer burn of the Centaur stage to compensate, and Voyager 1's mission to Jupiter, Saturn, and beyond began.
Voyager 1's journey to the launchpad began with the "Grand Tour" concept of the 1960s, in which Gary Flandro of the Jet Propulsion Laboratory (JPL) noted an alignment of Jupiter, Saturn, Uranus, and Neptune would occur in the 1970s, allowing a probe to swing by all the planets by using gravity assists. //
Voyager 1 could have performed the same Grand Tour as Voyager 2, and would have if disaster had befallen the latter at or soon after launch. However, it was Voyager 2 that swung past Uranus and Neptune, while Voyager 1 took a trip past Titan before finally heading away from the planets. It used its cameras to take one last set of images – the famous "Solar System Family Portrait," comprising six of the solar system's eight planets and, of course, the "Pale Blue Dot" image.
Voyager took the images on February 14, 1990. "That was always our farewell thing," said Hunt. "That was our Valentine's present for 1990."
Farewell? Not quite. Voyager 1 continues to send data back to Earth, 48 years after its launch.