Author Topic: Mars EDL technologies  (Read 162790 times)

Offline AnalogMan

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Re: Mars EDL technologies
« Reply #260 on: 05/28/2014 11:20 pm »
NASA’s Low-Density Supersonic Decelerator Tests New Deceleration Technologies
The Marshall Star - May 28, 2014

NASA’s Low-Density Supersonic Decelerator (LDSD) test is designed to investigate new deceleration technologies that could help land heavier payloads on planets like Mars. The test will take place at the U.S. Navy’s Pacific Missile Range Facility in Kauai, Hawaii, with the first potential launch date June 3.

Additional potential test dates include June 5, 7, 9, 11 and 14. The launch window for each date extends from noon - 1:30 p.m. CDT. Decisions to attempt launch of the LDSD test will be made the day before each launch opportunity date.

During the experimental flight test, a large balloon about the size of three football fields will carry the saucershaped test vehicle to an altitude of about 120,000 feet. It will then be dropped and its booster rocket will quickly kick in and propel it to 180,000 feet, reaching Mach 4. Once in the very thin air high above the Pacific, the first deceleration device, called a Supersonic Inflatable Aerodynamic Decelerator, -- the world’s largest -- will deploy, inflate and slow the vehicle.

A short time later the second deceleration device, a 30.5 meter parachute -- which is the world’s largest supersonic parachute and double the size of the one used on the recent Mars Science Laboratory mission -- will deploy and slow the vehicle further before landing in the ocean.

Current technology used for decelerating large payloads dates back to NASA’s Viking program from the ‘70s. In order to send humans and required equipment to Mars, new ways of slowing down heavy payloads through the atmosphere are critical.

Anyone with Internet access will be able to watch the test live as video is relayed from the vehicle to the ground. Websites providing coverage will include NASA TV and via Ustream at http://www.ustream.tv/nasajpl2. The LDSD Web page will also have daily updates on launch attempts, as well as the Twitter accounts @NASA_Technology, @NASA and @NASA_Marshall.

NASA’s Space Technology Mission Directorate in Washington funds the LDSD mission, a cooperative effort led by NASA’s Jet Propulsion Laboratory. NASA’s Marshall Space Flight Center manages LDSD within the Technology Demonstration Mission Program Office.

NASA’s Wallops Flight Facility is coordinating support with the Pacific Missile Range Facility and providing the balloon systems for the LDSD test.

http://www.nasa.gov/sites/default/files/files/star140528.pdf

Offline AJA

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Re: Mars EDL technologies
« Reply #261 on: 05/29/2014 09:08 pm »
Aah.. thanks guru, and Jim. I guess I read SIAD, but pictured HIAD. But since they've successfully tested IRVE, do they need to continue with SIAD? Or are they both part of the same project?


EDIT: Also, didn't Allen and Eggers show, from first principles, that the heating load is inversely proportional to the drag co-efficient? Which led to blunt body re-entries? Is that not applicable to such a decelerator for some reason? i.e. Increase the area, and thus the drag co-efficient, and ameliorate the heating problem?
« Last Edit: 05/30/2014 06:20 am by AJA »

Offline catdlr

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Re: Mars EDL technologies
« Reply #262 on: 05/29/2014 10:41 pm »
May 29, 2014
MEDIA ADVISORY M14-097

NASA Sets Media Coverage for Saucer-Shaped Test Vehicle Flight in Hawaii

http://www.nasa.gov/press/2014/may/nasa-sets-media-coverage-for-saucer-shaped-test-vehicle-flight-in-hawaii/#.U4e2HPldWkE
« Last Edit: 05/29/2014 10:42 pm by catdlr »
Tony De La Rosa

Offline catdlr

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Re: Mars EDL technologies
« Reply #263 on: 05/30/2014 12:24 am »
NASA Coverage for Saucer-Shaped Test Vehicle Flight

http://www.jpl.nasa.gov/news/news.php?release=2014-168

Quote
On launch attempt days, journalists are invited to PMRF to watch the liftoff and flight of the balloon carrying the LDSD. June 3 is the first launch attempt day, with a launch window extending from 8 to 9:30 a.m. HST (11 to 12:30 PDT/2 to 3:30 EDT).

NASA's LDSD carries several onboard cameras. It is expected that video of selected portions, including the rocket-powered ascent, will be downlinked live and streamed live to NASA TV and online.

The public may watch the news conference on June 2, and the balloon launch and subsequent test on June 3, on NASA TV
« Last Edit: 05/30/2014 12:26 am by catdlr »
Tony De La Rosa

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Re: Mars EDL technologies
« Reply #264 on: 06/02/2014 08:03 pm »
http://www.jpl.nasa.gov/news/news.php?release=2014-169&utm_source=iContact&utm_medium=email&utm_campaign=NASAJPL&utm_content=DailyBreakly20140602

NASA's 'Flying Saucer' Readies for First Test Flight
June 02, 2014

The first launch opportunity for the test vehicle is June 3, when the launch window opens at 8:30 a.m. Hawaii Standard Time (11:30 a.m. PDT/2:30 p.m. EDT). The test will be carried live on NASA TV and streamed on the Web. The Low Density Supersonic Decelerator (LDSD) will gather data about landing heavy payloads on Mars and other planetary surfaces.
« Last Edit: 06/02/2014 08:04 pm by Blackstar »

Offline catdlr

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Re: Mars EDL technologies
« Reply #265 on: 06/02/2014 08:43 pm »
Inflatable Heat Shields Could Drop-Ship Bigger Robots | Video

Published on Jun 2, 2014
The Hypersonic Inflatable Aerodynamic Decelerator, or HIAD, is rigorously tested in NASA's Armstrong Flight Research Center. This technology is being developed to deliver larger payloads to planets more efficiently.

Tony De La Rosa

Offline guru

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Re: Mars EDL technologies
« Reply #266 on: 06/02/2014 09:44 pm »
Aah.. thanks guru, and Jim. I guess I read SIAD, but pictured HIAD. But since they've successfully tested IRVE, do they need to continue with SIAD? Or are they both part of the same project?


EDIT: Also, didn't Allen and Eggers show, from first principles, that the heating load is inversely proportional to the drag co-efficient? Which led to blunt body re-entries? Is that not applicable to such a decelerator for some reason? i.e. Increase the area, and thus the drag co-efficient, and ameliorate the heating problem?

The drag coefficient is not synonymous with the drag.

Drag is equal to the product of the drag coefficient, the total dynamic pressure (which is directly proportional to air density and to the square of the velocity), and the facing surface area.

Doubling the diameter will double the Reynolds number, but this won't generally result in more than about a 10% change in the drag coefficient  - usually, that 10% is a decrease, unless you happen to just hit the sweet spot on the Re number axis, and at higher Reynolds numbers, the change in the drag coefficient vs the Reynolds number is essentially nil.  (Aerodynamics in the supersonic regime is in some ways simpler than in the subsonic one.)

But, doubling the diameter will quadruple the surface area.  So, assuming a constant mass, the vehicle endures four times the drag, meaning four times the deceleration, meaning as much as 4 times the rate of kinetic energy dissipation (that's the upper limit as decerlation time approaches infinity) over only 4 times the surface area, meaning that the heat flux either stays the same, or goes down.  In practice, over the time scale of a Mars EDL scenario, the heat flux is much closer to staying the same.  Add in the heat transfer effects caused by increased turbulence and a thinner thermal boundary layer, and one finds the possibility of a slight increase in total heat flux.  As you state, though, the heat flux will usually drop a small amount, so heat flux is not the issue I made it out to be.

In regards to peak g-forces, changes in density with altitude could give some advantage to a larger surface area earlier in the EDL process, meaning that with deceleration beginning higher up, one could spread out the deceleration some more, but how much it helps (if at all) depends on how much velocity is bled off prior to reaching the dense lower atmosphere.  If there is little velocity lost, than you wind up with nearly four times the g-forces at peak. If more than 75% of the velocity is bled off earlier, then the peak g-forces could go down.  For the cases considered, the increased area would still lead to much higher peak g-forces, but you can see that there are trade-offs and some optimization that goes into this.

More on the blunt body:  In a blunt body vehicle, the cushion of air helps keep the air flow in general, and the shock waves in particular, away from the vehicle.  Thus, a much larger portion of the dissipated kinetic energy (as much as 90%) gets carried away in the shock waves of a blunt body instead of being absorbed into the vehicle's hull, as would happen with sharper geometries.

As always, I am ready to be corrected if warranted.
« Last Edit: 06/02/2014 09:45 pm by guru »

Offline bolun

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Re: Mars EDL technologies
« Reply #268 on: 07/11/2014 11:42 pm »
That story has gotten badly reported--at least the headlines are misleading. They have led people to think that ESA is developing a helicopter for landing things on Mars when this was only a test device for Earth.

Offline manboy

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Re: Mars EDL technologies
« Reply #269 on: 10/09/2014 10:17 pm »
Planned Flight of the Terrestrial HIAD Orbital Reentry (16 June 2014)


"The Terrestrial HIAD Orbital Reentry (THOR) is planned for flight in 2016 as a secondary payload on an Orbital Sciences Corporation (OSC) commercial resupply mission to the International Space Station (ISS). THOR will launch with its Hypersonic Inflatable Aerodynamic Decelerator (HIAD) stowed as a small cylinder between the second stage motor and the Antares launch vehicle fairing. Once the Cygnus cargo vehicle has separated from the second stage, THOR will likewise separate, autonomously re-orient itself, perform a de-orbit burn, then inflate the HIAD to a 3.7m diameter cone before atmospheric interface."

"Authority to Proceed with THOR is anticipated by the start of fiscal 2015."
« Last Edit: 10/09/2014 10:24 pm by manboy »
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Offline guru

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Re: Mars EDL technologies
« Reply #270 on: 10/18/2014 10:24 pm »
NASA and SpaceX have released thermal video imaging of a night time supersonic retro-propulsive re-entry burn of a Falcon 9 rocket in Mars entry relevant conditions.

Watching it, I was amazed.  On the boost back burn, it was beautiful to see the entire ignition plume from a distance.  I also never really envisioned (although in hind sight I should have) the entire shock boundary layer being sloughed off.

The actual reentry burn itself looked rather more violent than I expected as well.  If you haven't seen it yet, enjoy.

http://aviationweek.com/space/thermal-images-spacex-falcon-9-rocket-descent

Original NASA press release:

http://www.nasa.gov/press/2014/october/new-commercial-rocket-descent-data-may-help-nasa-with-future-mars-landings/


Offline Robotbeat

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Re: Mars EDL technologies
« Reply #271 on: 10/19/2014 12:50 am »
Interesting how much trouble we'll go through (conceptually) to avoid supersonic retropropulsion, how skeptical people are that it could possibly work.... Until someone simply bothers to test it.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Online sdsds

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Re: Mars EDL technologies
« Reply #272 on: 10/19/2014 02:30 am »
Interesting how much trouble we'll go through (conceptually) to avoid supersonic retropropulsion, how skeptical people are that it could possibly work.... Until someone simply bothers to test it.

Yes I agree.

Except for the phrase, "simply bothers." You make it sound like this kind of testing was easy; like anyone with an afternoon to spare could have done it. I think that's underselling the boldness of SpaceX!
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Offline Dalhousie

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Re: Mars EDL technologies
« Reply #273 on: 10/20/2014 11:00 pm »
The first truly detailed Mars lander study (and the most detailed to date AFAIK) was the NA study of 1968.  They chose to go with supersonic retropropulsion after considering various options including ballutes.  They proposed a ballistic test program in the upper atmosphere. It's taken 46 years but we now know that the concept is sound.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Robotbeat

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Re: Mars EDL technologies
« Reply #274 on: 10/21/2014 01:24 am »
The first truly detailed Mars lander study (and the most detailed to date AFAIK) was the NA study of 1968.  They chose to go with supersonic retropropulsion after considering various options including ballutes.  They proposed a ballistic test program in the upper atmosphere. It's taken 46 years but we now know that the concept is sound.
Do you have a link? I don't see it here:
http://en.wikipedia.org/wiki/List_of_manned_Mars_mission_plans_in_the_20th_century
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Dalhousie

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Re: Mars EDL technologies
« Reply #275 on: 10/21/2014 01:56 am »
The first truly detailed Mars lander study (and the most detailed to date AFAIK) was the NA study of 1968.  They chose to go with supersonic retropropulsion after considering various options including ballutes.  They proposed a ballistic test program in the upper atmosphere. It's taken 46 years but we now know that the concept is sound.
Do you have a link? I don't see it here:
http://en.wikipedia.org/wiki/List_of_manned_Mars_mission_plans_in_the_20th_century

It was the lander that illustrates that article. :)

It was used in the Boeing IMIS (1968), the Von Braun Mars study (1969), the NASA Mars Expedition (1971) and a couple of others.

Not all of the source material is available, but if you search for "MEM" in the fora you should find the links to what is out there. If you can't I will upload them from home.

IMHO the design stands up very well, if we were to do a short stay Mars mission today we would still end up with something  like this.
« Last Edit: 10/21/2014 01:57 am by Dalhousie »
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Robotbeat

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Re: Mars EDL technologies
« Reply #276 on: 10/21/2014 03:31 am »
Thanks! I always am fascinate by Mars architectures, especially the older ones. Von Braun's Mars Project is my favorite for being fairly doable technically (except for scientific inaccuracies about Mars) and for using medium RLVs and vast amounts of on orbit refueling. It's the most ambitious on that list but I think it uses the least-powerful launch vehicle!
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Dalhousie

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Re: Mars EDL technologies
« Reply #277 on: 10/21/2014 09:22 am »
Were you able to download the relevant reports?
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline Robotbeat

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Re: Mars EDL technologies
« Reply #278 on: 10/22/2014 02:52 am »
Were you able to download the relevant reports?
yes. Looks like a capsule that lands on legs and has the center part launch as the ascent stage.
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Offline Dalhousie

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Re: Mars EDL technologies
« Reply #279 on: 10/22/2014 03:01 am »
That's it, simple and efficient.
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

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