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Mars Sample Return
John Whitehead
post Dec 18 2020, 04:50 PM
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Terrific news that real money will flow to MSR, and here is another quote from the same article.
QUOTE
Phase A... the program will mature critical technologies and make critical design decisions
These two steps will include figuring out how big the MAV really needs to be, and how much payload it really can carry (with or without the fetch rover on the same lander). During the December 16 meeting of the Steering Group for the Planetary Decadal Survey, there was a fine explanation from retired Pegasus launch vehicle developer Antonio Elias, of the MSR Independent Review Board. He said launch vehicle development typically starts with a payload mass goal, then they figure out how big the vehicle needs to be. Conversely, he noted that Pegasus started with a vehicle size (so it could be carried by the airplane), and the engineering challenge was to get the most payload that they could. He said the MAV is the first launch vehicle development to start out with fixed constraints on both ends (required payload mass to Mars orbit, and a total mass limit for delivery to Mars). This is going to be a cool project!

A video of this week's meeting might end up at the following link (not there at the moment, but some other recent meeting videos have been posted).
https://www.nationalacademies.org/event/12-...-2032-meeting-7
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mcaplinger
post Dec 18 2020, 05:36 PM
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QUOTE (John Whitehead @ Dec 18 2020, 08:50 AM) *
These two steps will include figuring out how big the MAV really needs to be, and how much payload it really can carry...

As noted upthread, back in April 2020 NASA showed every indication that they were ready to buy the flight rocket motors from NGIS ( https://beta.sam.gov/opp/349cbd728ab24d7693...true&page=1 )
One presumes that this never happened, reason unknown.

I've seen progress. It doesn't look like this.


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John Whitehead
post Dec 22 2020, 01:51 AM
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QUOTE (mcaplinger @ Dec 18 2020, 06:36 PM) *
One presumes that this never happened, reason unknown.
See Post number 389 above, second paragraph under the heading "summary of events" in 2020, namely that it is hard to nail down how big the MAV is going to be. So the choices are:
1. Buy the motors, build prototype MAVs and do some test flights (expensive testing with evolutionary progress toward a final design like SpaceX does), or
2. Continue trying to converge toward a final design on paper (less costly like ULA is doing for the Vulcan launch vehicle, but harder to do for the MAV in the absence of sufficient experience building miniature launch vehicles).
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Steve G
post Feb 9 2021, 02:14 PM
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Is the sample return mission going to be NASA's next planned Mars mission? I see nothing on the books for any approved, or even a firm proposal, past Perseverance for a NASA Mars mission. When can we expect approval for the next mission?
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mcaplinger
post Feb 9 2021, 04:33 PM
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QUOTE (Steve G @ Feb 9 2021, 06:14 AM) *
Is the sample return mission going to be NASA's next planned Mars mission?

Currently yes, though not yet committed to AFAIK (it's been "approved for phase A" but I'm not convinced it's fully funded at that level in the FY2021 budget, maybe somebody who's waded through the budget knows more.)

MEPAG docs are the best source of information. https://mepag.jpl.nasa.gov/meetings.cfm

https://mepag.jpl.nasa.gov/meeting/2021-01/...1_2021%20V5.pdf

https://mepag.jpl.nasa.gov/meeting/2021-01/...2021%20v1.1.pdf


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mcaplinger
post Feb 12 2021, 12:42 AM
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QUOTE (mcaplinger @ Feb 9 2021, 08:33 AM) *
it's been "approved for phase A" but I'm not convinced it's fully funded at that level in the FY2021 budget, maybe somebody who's waded through the budget knows more.

http://spaceref.com/news/viewsr.html?pid=54522 says
QUOTE
Exceeding NASA’s request, Congress is providing $264 million for the Mars Sample Return mission, with direction to have it ready for the launch window that opens in 2026.



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John Whitehead
post Feb 12 2021, 06:01 AM
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After the MSR presentation to MEPAG on 2021Jan27 (middle link in Post number 395 above), one of the questions was whether the MSR schedule and budget includes iterative building and testing to converge on a final MAV design, considering that uncertainty remains after years of past trade studies. The NASA HQ reply was that analysis should be sufficient, and testing will only be needed to validate the design. This statement seems to lean toward option 2 in Post 393.

The Q&A described here starts at time 2:14:30 in the following video of the meeting.
https://mepag.jpl.nasa.gov/meeting/2021-01/...l%20Meeting.mp4
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Explorer1
post Feb 27 2021, 04:26 AM
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Some good details about the fetch rover and MAV in this PBS documentary (around 40 min in): https://www.youtube.com/watch?v=fhtw7Dpntb4
Worth watching on its own, too!
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John Whitehead
post Feb 27 2021, 06:37 AM
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Thanks for that link. Yes there are good details about the fetch rover, especially that prototype testing is ongoing. But there are no details about the MAV, only that it is a "pint size rocket" (not true) and the statement from ESA that the MAV is the hardest part of the whole mission, "super ambitious" (true). Then the animation shows the entire MAV reaching Mars orbit, without dropping the first stage (huh?). One has to wonder why the crack team of miniature launch vehicle engineers was not featured in this NOVA show, testing their prototype rockets and explaining the challenges they are working on.
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mcaplinger
post Mar 4 2021, 09:31 PM
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https://www.nasa.gov/press-release/nasa-awa...r-sample-return

QUOTE
The cost-plus, fixed-fee contract has a potential mission services value of $60.2 million and a maximum potential value of $84.5 million. Work on MAPS begins immediately with a 14-month base period, followed by two option periods that may be exercised at NASA’s discretion...
Marshall is responsible for the MSR Program’s MAV element, which is a two-stage vehicle that will be a critical element in supporting MSR to retrieve and return the samples that the Mars 2020 Perseverance rover will collect for return to Earth. The Martian environment will be a significant factor in the design, development, manufacturing, testing, and qualification of two different solid rocket motors with multiple deliveries of each. Through the MAPS contract, Northrop Grumman will provide the propulsion systems for the MAV, as well as other supporting equipment and logistics services.



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John Whitehead
post Mar 6 2021, 06:37 PM
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QUOTE (mcaplinger @ Mar 4 2021, 09:31 PM https://www.nasa.gov/press-release/nasa-awards-mars-ascent-propulsion-system-contract-for-sample-return) *
14-month base period, followed by two option periods that may be exercised at NASA’s discretion
This contract for MAV solid rocket motors (SRMs) is a major step forward--finally real money for a MAV! A mere 14 months seems too short for flight deliverables, so this base period with options suggests a development project, versus having a final design that is straightforward to build. Ideally such an effort would have started ten years ago, to allow more time to work through uncertainties. Regarding the overall timing for MSR, it is encouraging that recent decades have seen huge improvements in at least two key technologies, inertial navigation instruments small enough for a MAV, and electric propulsion (for the Earth Return Orbiter, ERO).

Attached to this post is a MAV chart from a public presentation to the National Academies Planetary Decadal Steering Committee on February 11, with key points in my added sidebar and detailed comments below. DecadalMAV2021Feb11.pdf

In size, shape, and mass, the first stage SRM is very much like the 300-kg STAR 20 SRM that has decades of flight heritage and a terrific propellant fraction, about 90 percent. The challenges are to make a nozzle that can swivel without adding undue mass, and to reduce the thrust to about one-third of the STAR 20 (1700 lb versus over 5000 lb). Solid propellant burns at its own rate for a given formulation, so it is not necessarily easy to make it burn three times slower. Alternatively, the internal geometry might be changed to reduce the area of the burning surface. Assuming that 1700 lb works out, there will be plenty of thrust to flight-test the MAV in Earth gravity.

While STAR motors for space applications are mostly spherical in shape, the second stage SRM is shown here as a short cylinder, not ideal structurally for internal pressure. Presumably there will be some development work to make the case sufficiently lightweight.

History shows that it is a major challenge to make all the MAV parts sufficiently lightweight, relative to the propellant and the payload. One year ago in March 2020 (IEEE Aerospace Conference), the two-stage solid MAV design had the same total mass (400 kg) and payload (16 kg). In the fall, the report from the MSR Independent Review Board revealed that the design had grown to over 500 kg, but switching to an unguided upper stage would reduce it to 320 kg. Stage 2 would be made lighter by leaving the liquid steering propulsion and inertial navigation instruments on Stage 1, so that Stage 2 becomes a point-and-shoot. According to a presentation to the Decadal Survey Mars Panel on 2021Jan5, the 320-kg MAV was up to 380 kg. As of Feb11 it was back to 400 kg, just like the design from one year ago, despite the risky unguided upper stage that was expected to reduce the MAV mass.

The take-away is that the year-old design must have had unrealistic assumptions for making the parts lightweight, and there might still be some extra optimism. One risk for the spinning upper stage is that it won't be put on a spin-balancing machine after the Mars geology samples are installed, so will it stay pointed in the right direction after spin-up and during the burn? After the de-spin motors fire, what is the allowable amount of residual rotation (tumbling) for the stage to eject the orbiting sample to the ERO?

After Perseverance landed on 2021Feb18, the public video feed included a feature about the Mars helicopter, Ingenuity. They showed a team of enthusiastic creative engineers doing trial-and-error flight testing, and it was specifically pointed out that the helicopter design is all about having high electrical power while being super lightweight. Hopefully we will one day see a similar news feature that documents the efforts of a successful MAV team to make all the parts super lightweight relative to the propellant and payload.
Attached File(s)
Attached File  DecadalMAV2021Feb11.pdf ( 152.71K ) Number of downloads: 170
 
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Explorer1
post Jun 7 2021, 04:44 PM
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A good article with some details about the MAV, including initial launch (a spring into the air before ignition!):

https://www.nasaspaceflight.com/2021/06/mar...vehicle-update/
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John Whitehead
post Jun 18 2021, 07:06 PM
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That June 4 article (Post #402) is titled "Mars Ascent Vehicle from Northrop Grumman..." The text includes, "NASA formally awarded the MAV contract to Northrop Grumman," and "Northrop Grumman will provide a 3 meter tall, two-stage, solid propellant rocket." These quotes seem to indicate that N-G is building the whole MAV, whereas the initial contract previously announced was only for the solid rocket motors (Post #400). The attachment below is more recent info from NASA HQ, as presented on June 14 to Mars scientists, with my notes added in yellow boxes. HQ said they are now working on a contract for the whole MAV, but did not name a particular contractor.

The June 4 article quotes Dave McGrath, who has been at the Maryland solid rocket plant (formerly Thiokol) for decades. Dave was always spoken of highly by George Sutton of rocket textbook fame, who passed away in October at age 100. So we know that the expertise is there for solid propellant and solid rocket motors, which is great, but the big unknown is putting a whole MAV together and making it fly correctly when all the parts are made super-lightweight in order to meet the required performance to reach Mars orbit. From Post #400 above, the solid motor contract is something like $80 million. Likely the cost will be roughly ten times that, to bring a whole MAV to fruition.

If Northrop-Grumman does build the whole MAV, it would presumably be the piece of the company previously known as Orbital Sciences Corporation (OSC) from 1982 to 2014. In mid-2020, the original founders of OSC served on the MSR Independent Review Board (IRB) as the Chair and as the launch vehicle expert. Small world.

Looking back two months, the quoted question below was submitted to a NASA Science "town hall" public meeting on 2021Apr20. The answer from NASA HQ was non-specific, consistent with significant remaining uncertainty and a lot to be learned. Future updates will be interesting.
QUOTE (NASA SMD Town Hall April 20, 2021, questions can be seen at https://arc.cnf.io/sessions/ta79/#!/dashboard)
How does flight testing of the Mars ascent vehicle fit into the aggressive schedule for MSR? No planetary mission would be trusted to a brand-new launch vehicle for Earth departure, so we shouldn't trust the most expensive planetary mission ever to an untested launch vehicle for Mars departure.
Here is the video of the April 20 meeting, and the question is asked 5 minutes before the end of the meeting, at time 53:20. I still wish the moderator had read my entire paragraph, which makes a key point that continues to be downplayed.
https://www.youtube.com/watch?v=8LZdbzHsfZo
Attached File(s)
Attached File  MSRslidesNASAhq2021Jun14withNotes.pdf ( 536.32K ) Number of downloads: 90
 
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bobik
post Jul 26 2021, 08:42 AM
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Integrated Design Results for the MSR DAC-0.0 Mars Ascent Vehicle. [Paper][Presentation]

DAC-0.0 performed January - June 2020 to advance fidelity of MAV design for NASA Key Decision Point A (KDP-A) --> KDP-A completed in December 2020 following additional architecture updates --> After DAC-0.0, MSR campaign determined it had insufficient mass & volume margins within entire lander system --> Modifications to MAV architecture traded ~145kg at the expense of orbital insertion accuracy.
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John Whitehead
post Jul 27 2021, 05:30 PM
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Thanks to bobik for posting the links to the MSFC paper and presentation charts from the March 2021 IEEE Aerospace Conference, and for quoting those four lines from the presentation charts.

The paper indicates 525 kg for the DAC-0.0 MAV design, so the 145-kg reduction yields 380 kg, which equals the January number for the MAV having a spinning upper stage, later shown as 400 kg in February (two different presentations to the Planetary Decadal Survey, as noted in Post #401).

On June 21, the MSR presentation from NASA HQ to MEPAG said that they are still studying one versus two landers, with a decision expected at the end of Phase A. The extra lander would be needed to deliver the fetch rover if the MAV is heavy, so either the DAC-0.0 design is still under consideration, or there is a concern that the newer design might need to be heavier than 380 to 400 kg.

The June 21 presentation showed that formal reviews (PDR and SRR) already happened in April for the Earth Return Orbiter, the Sample Fetch Rover, and the Capture, Containment, and Return System. Compared to all this progress, the MAV seems to be less far along.
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