To my knowledge, there has never been an instance in which a descent engine, on any lunar landing spacecraft has been reignited on the lunar surface in order for the landing spacecraft to get back into orbit.
The Apollo LM Ascent Engine wasn't burdened by the convoluted plumbing associated with the cryogenic propellant engines on Starship. Nor was it exposed to any rocks blasted around during landing, or any rocks at all. The LM used hypergolic fuels so the engines were 'simple' and there was actually a backup process for ignition if the Ascent Engine failed to light up when the button was pressed. The Ascent Engine was also tested a huge number of times, including during the Apollo 5 unmanned test flight.The Soviet LK *did* reuse the Descent Engine for launch, but had a protective shroud over it at the point of landing. And, on the LK, there was a backup engine!All of these differences suggest that the Lunar Starship demo flight *should* include a launch from the surface, either to orbit or back to a second landing on the surface.
On Starliner, at least there was a pad abort test which maybe encompasses some of the same regime and data as a flight abort test.But there’s nothing like that to point to on EUS or HLS lunar ascent testing before astronauts are involved. Absent explanation or change, they’re both boneheaded moves.Even on COTS, with no astronauts on board involved, the program still did full orbital and ISS rendezvous and docking demos before handing off to CRS.
What Nasa got right on the Apollo lunar landings is luck. All their tests, if I remember right led them to the premise that the Assent engine would always ignite. (That is the luck).
Quote from: whitelancer64 on 10/21/2022 09:19 pmQuote from: VSECOTSPE on 10/21/2022 05:35 pmQuote from: yg1968 on 10/21/2022 05:00 pmNASA Orders Three More Orion Spacecraft From Lockheed Martin:https://news.lockheedmartin.com/2022-10-20-NASA-Orders-Three-More-Orion-Spacecraft-from-Lockheed-MartinFrom that press release:QuoteUnder OPOC, Lockheed Martin and NASA have reduced the costs on Orion by 50% per vehicle on Artemis III through Artemis V, compared to vehicles built during the design and development phase. The vehicles built for Artemis VI, VII and VIII will see an additional 30% cost reduction.These claims don’t match the Orion budget. Artemis IV launches in 2027 under the baseline and content manifests. According to this LockMart press release, Orion’s budget should come down by about half by then, or at least around $700 million from its peak of over $1.4 billion a couple years earlier. But NASA’s FY 2023 budget request shows Orion still consuming $1.1 billion in FY 2027.It’s nice that the Orion Program may finally have its arms around costs and that they may be coming down modestly. And I’m sure a LockMart accountant could show how the Orion for Artemis IV is 50% of the Orion for Artemis I by excluding a lot of costs. But in terms of what NASA and the US taxpayer actually have to cough up for Orions, OPOC and the Orion Program are not coming in anywhere near their cost goals and claims.Yeah, "cost per vehicle" definitely isn't including other Orion program costs. They are planning on reusing the capsule from Artemis 3 on Artemis 6, 4 on 7, and 5 on 8, that's playing a huge part of that 50% cost reduction.No mention of European built and paid for service modules for these missions.
Quote from: VSECOTSPE on 10/21/2022 05:35 pmQuote from: yg1968 on 10/21/2022 05:00 pmNASA Orders Three More Orion Spacecraft From Lockheed Martin:https://news.lockheedmartin.com/2022-10-20-NASA-Orders-Three-More-Orion-Spacecraft-from-Lockheed-MartinFrom that press release:QuoteUnder OPOC, Lockheed Martin and NASA have reduced the costs on Orion by 50% per vehicle on Artemis III through Artemis V, compared to vehicles built during the design and development phase. The vehicles built for Artemis VI, VII and VIII will see an additional 30% cost reduction.These claims don’t match the Orion budget. Artemis IV launches in 2027 under the baseline and content manifests. According to this LockMart press release, Orion’s budget should come down by about half by then, or at least around $700 million from its peak of over $1.4 billion a couple years earlier. But NASA’s FY 2023 budget request shows Orion still consuming $1.1 billion in FY 2027.It’s nice that the Orion Program may finally have its arms around costs and that they may be coming down modestly. And I’m sure a LockMart accountant could show how the Orion for Artemis IV is 50% of the Orion for Artemis I by excluding a lot of costs. But in terms of what NASA and the US taxpayer actually have to cough up for Orions, OPOC and the Orion Program are not coming in anywhere near their cost goals and claims.Yeah, "cost per vehicle" definitely isn't including other Orion program costs. They are planning on reusing the capsule from Artemis 3 on Artemis 6, 4 on 7, and 5 on 8, that's playing a huge part of that 50% cost reduction.
Quote from: yg1968 on 10/21/2022 05:00 pmNASA Orders Three More Orion Spacecraft From Lockheed Martin:https://news.lockheedmartin.com/2022-10-20-NASA-Orders-Three-More-Orion-Spacecraft-from-Lockheed-MartinFrom that press release:QuoteUnder OPOC, Lockheed Martin and NASA have reduced the costs on Orion by 50% per vehicle on Artemis III through Artemis V, compared to vehicles built during the design and development phase. The vehicles built for Artemis VI, VII and VIII will see an additional 30% cost reduction.These claims don’t match the Orion budget. Artemis IV launches in 2027 under the baseline and content manifests. According to this LockMart press release, Orion’s budget should come down by about half by then, or at least around $700 million from its peak of over $1.4 billion a couple years earlier. But NASA’s FY 2023 budget request shows Orion still consuming $1.1 billion in FY 2027.It’s nice that the Orion Program may finally have its arms around costs and that they may be coming down modestly. And I’m sure a LockMart accountant could show how the Orion for Artemis IV is 50% of the Orion for Artemis I by excluding a lot of costs. But in terms of what NASA and the US taxpayer actually have to cough up for Orions, OPOC and the Orion Program are not coming in anywhere near their cost goals and claims.
NASA Orders Three More Orion Spacecraft From Lockheed Martin:https://news.lockheedmartin.com/2022-10-20-NASA-Orders-Three-More-Orion-Spacecraft-from-Lockheed-Martin
Under OPOC, Lockheed Martin and NASA have reduced the costs on Orion by 50% per vehicle on Artemis III through Artemis V, compared to vehicles built during the design and development phase. The vehicles built for Artemis VI, VII and VIII will see an additional 30% cost reduction.
Quote from: clongton on 10/24/2022 08:06 amTo my knowledge, there has never been an instance in which a descent engine, on any lunar landing spacecraft has been reignited on the lunar surface in order for the landing spacecraft to get back into orbit. EVERY "return to orbit" flight has been with a completely different - unused - ascent engine. Again, what did Apollo get right that they are missing in this case?
To my knowledge, there has never been an instance in which a descent engine, on any lunar landing spacecraft has been reignited on the lunar surface in order for the landing spacecraft to get back into orbit. EVERY "return to orbit" flight has been with a completely different - unused - ascent engine.
Jim Free says science is his biggest partner on Artemis and they've just allocated 450 kg to the surface for science on the first lander.
Here is a conference (Ascend) that discusses Artemis among other topics:vimeo.com/763203729
Did Apollo 10 test the ascent engine in the low lunar orbit environment by jettisoning the descent stage?
Quote from: JohnFornaro on 10/24/2022 11:55 amQuote from: clongton on 10/24/2022 08:06 amTo my knowledge, there has never been an instance in which a descent engine, on any lunar landing spacecraft has been reignited on the lunar surface in order for the landing spacecraft to get back into orbit. EVERY "return to orbit" flight has been with a completely different - unused - ascent engine. Again, what did Apollo get right that they are missing in this case?There was a LOT of discussion of the LM's ascent engine and it was tested over and over again. The "guarantee" that the engine would always ignite, if you will allow, was two-fold. (1) the ascent engine was protected from lunar debris contamination or damage by being enshrouded above the descent stage. Nothing would hurt it. (2) The propellants were hypergolic. Basically, open the 2 valves and you've got ignition. I'm not even sure if the tanks were pressurized or not (anybody know?). With the LM sitting on the surface, once you opened the propellant valves, lunar gravity "could" do the rest and they lifted off. G-force acceleration kept the propellants settled in the bottom of the tanks at the engine inlets.It's different with the Starship(1) the descent engines ARE the ascent engines and, even though they're higher up, are exposed to any flying debris resulting from the landing.(2) the propellants are NOT hypergolic and igniting the engines requires the successful completion of a whole series of ignition sequence events. If any one of them fails to complete there is no ignition.THAT's why I say that NASA is bat-crap crazy to not require a clear demonstration that Starship actually can reignite the engines after they have been off for however long, bring to full power and return to lunar orbit, BEFORE, they put crew onboard to potentially be stranded on the surface. Every Raptor engine reignition up until now has always been after the previously ignited engine was inspected post firing. I don't see that as an option here, UNLESS the interior of Starship where the engines are mounted is actually outfitted as an "engine room"?
Quote from: whitelancer64 on 10/21/2022 09:19 pm*snip*They are planning on reusing the capsule from Artemis 3 on Artemis 6, 4 on 7, and 5 on 8, that's playing a huge part of that 50% cost reduction.No mention of European built and paid for service modules for these missions.
*snip*They are planning on reusing the capsule from Artemis 3 on Artemis 6, 4 on 7, and 5 on 8, that's playing a huge part of that 50% cost reduction.
There isn't any mention of the 6 Apollo LM descent stages having been damaged by regolith impingement in the respective mission tech debriefs. The descent engine was operating within 1.7m (contact leg length) of the surface at touchdown and there was certainly evidence of interaction (dust plume), but the astronauts' only observations were about some charred insulation (A11) and various rocks seen under the descent stage. Given that the current HLS design is predicated on using thrusters (located ~25m above the rocket's base) within 100m of the surface, there's certainly no evidence for claims that regolith impingement would be a significant issue. It seems that Elon would like to eliminate those thrusters (per his comments to Tim Dodd), but qualifies that by saying it depends on whether "... SpaceX is able to demonstrate that landing on the moon with Raptor will not create too large of a hole in the lunar regolith... ".As for testing Raptor re-ignition without post-firing inspections, I'll recommend the NASA Spaceflight video "SpaceX Tests Raptor Rapid Relight Capability" that was posted today...
Here is a conference (Ascend) that discusses Artemis among other topics:
Given that the current HLS design is predicated on using thrusters (located ~25m above the rocket's base) within 100m of the surface, there's certainly no evidence for claims that regolith impingement would be a significant issue.
Quote from: JohnFornaro on 10/24/2022 11:55 amQuote from: clongton on 10/24/2022 08:06 amTo my knowledge, there has never been an instance in which a descent engine, on any lunar landing spacecraft has been reignited on the lunar surface in order for the landing spacecraft to get back into orbit. EVERY "return to orbit" flight has been with a completely different - unused - ascent engine. Again, what did Apollo get right that they are missing in this case?There was a LOT of discussion of the LM's ascent engine and it was tested over and over again. [Emphasis mine]The "guarantee" that the engine would always ignite, if you will allow, was two-fold. (1) the ascent engine was protected from lunar debris contamination or damage by being enshrouded above the descent stage. Nothing would hurt it. (2) The propellants were hypergolic. Basically, open the 2 valves and you've got ignition. I'm not even sure if the tanks were pressurized or not (anybody know?). With the LM sitting on the surface, once you opened the propellant valves, lunar gravity "could" do the rest and they lifted off. G-force acceleration kept the propellants settled in the bottom of the tanks at the engine inlets.*snip*
Looking ahead at 1hr of the video (see also the attached slide):
