Sorry, you did *not* mention 5 km/s.

@itzly - you said that you "didn't know the details for Mars":

The speed of sound at atmospheric interface is around 200m/s so take your favorite realistic entry velocity at Mars and divide it by 200m/s to get the entry Mach number. (Spoiler: It won't be Mach 11)

Reference: http://exrocketman.blogspot.co... (look at figure 7 column 'c' is for the speed of sound)

Let's say we're *really slow* and enter at 5 km/s as you mentioned above. That would mean 5000/200 = Mach 25. A more realistic *direct* entry velocity is in the neighborhood of 6-7 km/s.

It's a SIAD (supersonic inflatable aerodynamic decelerator) the low density part of the LDSD acronym isn't because Mars has a low density. It comes from the fact that an inflatable device provides drag area at a much lower mass cost than your normal rigid structure.

NASA did develop these systems >50 years ago then some of it later trickled into the military to slow down dumb bombs etc. Now that the landing goals are expanding to even larger landed masses this technology is being far better expanded, developed and space flight qualified. For instance, the small ram-air inflated device behind a bomb is not nearly as challenging as a SIAD around a 4.5 meter diameter aeroshell.

Rigid articles are forgiving when you scale them down for aerodynamics and behavior. Flexible goods need to be tested at full scale or larger to get the right behavior.

To correct the above comment:

1) Parachutes are normally ripped apart somewhere between Mach 2 and Mach 3. A Mach 11 parachute is current-technology crazy.

2) You are likely talking about the HIAD (hypersonic inflatable aerodynamic decelerator) work that Langley is doing. The idea there is to inflate the inflatable decelerator (that has flexible TPS) in orbit before entry. Langley has had good success with two or three Earth orbital reentry tests of the HIAD system. They are doing great work there.

3) The large ~100ft diameter parachute is not opened at Mach 4. It is opened somewhere around Mach 2. It is novel because it is larger than what any wind tunnel currently on Earth can test and it is an effort to flight qualify a new higher performance drag parachute for Mars use. The parachute is completely separate from the inflatable decelerator.

4) Your speed during entry depends on your entry trajectory which varies based on opportunity. Divide by the speed of sound and you have Mach #. There is nothing special about Mach 11 that ties it to the "orbital velocity".

5) Both the HIAD and SIAD systems are being developed and have their own advantages. Both are being developed to good effect.

Please forgive the numbered lists

To flush out this story:

1) This is the first of three tests. The next test is next summer; they designed the long lead time so that they could roll bug fixes uncovered in the first test into the system. The price tag covers all the tests and some additional work besides not just this one test.

2) The black box was dropped just in case they couldn't recover the hardware, it has a lot of data and high resolution imagery. For this test, they were able to recover all of the hardware as well.

3) The first test was really a shake out of the balloon deployment method that took the vehicle up to 120k feet, spun it up for stability, brought it to Mach 4 and despun the vehicle. This hadn't been tried before so the fact that it succeeded was fantastic.

4) The gravy part of this test was the inflation of the SIAD (supersonic inflatable aerodynamic decelerator) and a new type of parachute with a higher drag coefficient than what we normally expect from a Viking heritage DGB (disk gap band). The SIAD inflated without a hitch the parachute looks to have tangled up. They'll have to investigate the hardware and find out what exactly happened.

5) They're doing something high risk and "crazy" to push forward the state of the art. Elements are expected to fail along the way but they're rolling fixes into the next test. Try checking out a compilation of rocket explosions that happened while we were learning how to build them.

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Why the hell does this matter?

With the current state of the art; we can land up to around 2 tons on Mars. With new technology like the SIAD (which can be opened far earlier than a parachute ever could be) we can get to landing ~10 tons on Mars. There is an even larger SIAD that would push this into the +20 ton range (especially if you include the new parachute as well). This is the start of the range where we can start talking about human missions to Mars.

Hope that helps.

No, all the components (at least for this test) were recovered for examination. It takes about two days to boat out to the site, pick up the items and bring them back for investigation. In case something unforeseen happened, a robust blackbox was dropped "just in case".