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WooHoo! We've Landed on Mars Again!

ppilotmike

Well Known Member
Perseverance has touched down successfully on the red planet today! To keep this thread RV related, I'm sure there were lots of RV Builders / Flyers who helped out on this mission. What a great success! Congrats to everyone who worked on / are working on this.

[ed. Outstanding! I was watching the feed of Mission Ctrl and got goose bumps. Went outside later and looked up at the sky at Mars. Going to be some amazing science over the next year from that vehicle. And it's nice to hear some of the RV folks that have tie ins with space exploration. v/r,dr]
 
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YAY!

I worked on a very early Mars airplane design activity, and then worked on the ARES Mars airplane, a project led from NASA Langley in 2003-2004, in competition for the 2007 Mars Scout mission. We finished 2nd in the selection process out of 26 proposals, just behind Phoenix Mars Lander. I have to say that the ARES project was just about the most fun, enlightening, and satisfying project of my career. It was an absolute joy to work with the whole team at Langley. The project has been re-proposed a couple of times since. I still hope that our baby will get a ride to Mars some day.

At about the same time, Larry Young at Ames was doing some conceptual design studies for a Mars helicopter. I was asked to review his work for feasibility and indeed, it would work - his performance estimates were very reasonable, and I advocated strongly for him to be allowed to pursue the concept. I do not know if Larry had a role in designing the current Mars helicopter that just landed with Perseverance. One of the appealing aspects of a rotorcraft is that it can fly multiple missions to interesting places (within a fairly small range) and return to a base station for re-charging, and at the same time bring samples back to a base for analysis (or encapsulation for a future sample-return mission).

One thing we did on the ARES airframe was use honeycomb sandwich material that was perforated and vented so it could breath out when put in a vacuum. Larry got some director's funding at Ames to do a wind tunnel test of a rotor, and he built the blades by wrapping glass over a foam core. When they pumped the test chamber down to Mars atmospheric pressures (about 1% of earth sea level pressure), the blades burst. Ooops! Live and learn.
 
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More about ARES

I know this is pretty far from RV related, so if a moderator wants to take it down, I would understand. But I think people would find it interesting.

If you want to learn more about the ARES Mars Airplane project, I think the website is still up. Just google it.

One of the last things we did was a full-up drop test from a balloon with a half-scale model of ARES. So, roughly 11-ft wingspan. A key task to demonstrate was the deployment and pull-up to level flight. The airplane rides to Mars in an entry capsule, all folded up. The wings fold across the middle kind of like the arms of a mummy in a tomb. Then the tail is folded under the belly like a lobster can curl its tail. So, when the airplane is dropped out of the backshell of the entry capsule, it has to unfold, in sequence. A drogue chute pulls the tail open, and also orients the vehicle in the flight path direction, which is about 50 degrees nose down. Then the wings unfold and latch, and the airplane begins a pull-up to level flight, which takes about 5km of the available 6km of altitude. (figuring out which way is 'up' at this point is a good trick) The drogue chute plays a key role here. Without it, the aircraft would over-speed in its dive, and at the high Mach no, would buffet without producing enough lift to pull up. So the drogue keeps the speed in check while the airplane starts pulling up. At a certain point, the drogue is slowing you down more than you would like, so you cut it loose and complete the pull-up. determining the best size of the drogue chute and timing when to cut it loose was a nice optimization problem. So - anyway, we dropped the half-scale model off a balloon at about 97,000 ft over Tillamook Oregon, and demonstrated the deployment and pull-up to level flight. There is a video of this on the website. As part of this, we think we set an unofficial record for the highest altitude that a wing-borne vehicle has ever made a 90-degree turn. As far as I know, no wing-borne vehicle had ever made a 90-degree turn at 96,000 ft. Not X-15. Not Helios. But ARES did. Several. It flew a box around four way-points until it got down to pattern altitude where it was landed 'by hand'.

ARES was designed to cruise at Mach 0.7, which on Mars is a TAS of about 400 mph, but an IAS of about 17 mph. There are some aerodynamic reasons why M=0.7 is a sweet spot. It was powered by a hypergolic rocket- Monomethylhydrazine and Nitrogen Tetroxide. We call it 'thrust you can trust'. I also did a study on how one might power the SECOND Mars airplane - using the same propellants in the same gas generator, but then expanding the gas through a turbine to drive a propeller. This system increased the endurance by a factor of five over the pure rocket, for the same propellant load. Yes -- we did look at electric power - that was the first early design study I worked on. Don't even get me started about the shortcomings.

Not just a stunt - our proposal, like all of the Mars Scout Mission proposals, was heavily science-driven. No one was going to spend $330M just to fly an airplane on Mars for the **** of it. It was not enough to say we were doing technology pathfinding. We chose compelling science missions that could only be obtained by an airplane, using instruments that filled crucial gaps in the research on past life, water, and planetary geology.

Really fun stuff.
 
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Thanks Steve

Good stuff, really interesting. And very nice to see a win for science yesterday.
 
It must've been quite an exercise to take everything you know about the physics of terrestrial flight and then translate them to martian atmospheric conditions.
 
I know this is pretty far from RV related, so if a moderator wants to take it down, I would understand. But I think people would find it interesting.

Really fun stuff.

Oh, this needs to be left on; off topic: yes. Of interest to us earth-bound adventurers? Yes!

It was AMAZING to follow the "flight" onto the surface several hundreds of thousands of miles away. When one considers how many things had to work PERFECTLY, it is beyond belief! I was in tears and was not alone!

Like the builders of the Lander, we are builders as well and there is a connection, as thin as it might seem. Their test flight was like ours (in an odd way): the first to fly a new craft!

I know I will be following the progress of this amazing spacecraft! This is how things work when a community of people work TOGETHER! Like this list, sort of.....:D
 
Things like this are not RV related, may be moved etc.

However, we were all Rootin' and Tootin' last night when Percy landed.

I am over here in Perfidious Albion, we still love what is going on in the Colonies...:D

Seriously, that was a stunning event - the landing method must have had some herbs involved at the planning stage, but heck, it worked !

Let's hope it now wanders around for a couple of year gathering data.
 
Seriously, that was a stunning event - the landing method must have had some herbs involved at the planning stage, but heck, it worked !
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Because the atmosphere is so thin, you can not get gentle descent rates with parachutes alone. well, reasonably sized ones anyway.
The early rovers dropped onto the surface inside a beach ball. When they did the Curiosity rover, they found that it was too heavy for the beach ball concept to work, and they had to figure out something different. But you don't want to burden the rover with having to carry around descent rockets for its whole mission life. So the Skycrane concept was born.

A brief story about parachutes. (kind of relevant for BRS systems)

At the conclusion of the earlier Mars Airplane design studies that I mentioned, all the design teams got together to try to coalesce all the knowledge and ideas that had emerged during the studies among the several groups. So there was a big meeting. This was around December 1999.

One of the members of the Langley team at that time was Juan Cruz, a lightweight-composites designer that had been part of the Daedalus project at MIT, along with Mark Drela, John Langford, Guppy Yungren, Bob Park, and a handful of other brilliant guys. So anyway, Juan Cruz brought up the issue of parachutes at the Mars Airplane design confab. We would need a parachute for the entry capsule, and we would need a parachute for the drogue to help with aircraft deployment. So Juan had this huge orange book that was like the bible for parachutes, and he plopped it onto the meeting table with a thud and said that someone needed to step up and become a parachute guru. There was a general quiet shuffling of feet and subtle backing away from the table, as if Juan had put a black mamba in the middle of the table. No one wanted to go anywhere near it. So Juan picked the book up and shrugged and said he guessed he would have a go at it.

Well, as it turned out, every single parachute that has been used for Mars missions since that time was designed by Juan, including the descent parachutes for Spirit, Opportunity, Curiosity, and now Perseverance. These were challenging development projects, with lots of trial and error and failure along the way. He did a parachute test in the NASA Ames 80 x 120 ft NFAC wind tunnel, where the canopy writhed like an octopus, where the flow on one side of the canopy would somehow trigger the collapse of the other side. He did a drop test from a helicopter where the whole canopy just shredded. But he got it all sorted out. No missions where ever delayed or failed because of problems with parachutes.
 
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Thanks to the Moderators..

..for letting this thread fly for a bit. Such an amazing achievement. My sincerest thanks to all those who worked to make it happen. My kids are so excited watching this and other recent successes in the pursuit of space exploration. Truly a wondrous example of what is possible, and great motivation to us builders, who in our own small way are also working hard to achieve a dream..
 
Because the atmosphere is so thin, you can not get gentle descent rates with parachutes alone. well, reasonably sized ones anyway.

What do you mean, thin? I saw a documentary once about Matt Damon's trip to Mars, and how he almost got killed in a windstorm strong enough to tip an entire spacecraft. The air looked pretty thick to me.

;)

In all seriousness, the skycrane idea is an amazing concept. I tried explaining it to my son yesterday, and simply trying to put it into words made it clear what a marvel of engineering it is. I remember reading about the helicopter / drone attached to the rover in (I think) Smithsonian Air and Space maybe a year ago. I look forward to hearing how it performs.

Fantastic work by all involved!!!
 
The little (read: incredibly light weight) helicopter was on display in the NASA building at Oshkosh a few years ago. Talked with one of the designers/testers and it was a significant effort to develop something that would fly autonomously in such a thin atmosphere. Can’t wait to see how/if it works! :cool:
 
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It must've been quite an exercise to take everything you know about the physics of terrestrial flight and then translate them to martian atmospheric conditions.

It is interesting that you point this out. Aero and propulsion folks that work in the Imperial units system (ft, lb_f, sec) cling to that unit system with the 'excuse' that we have more intuition for what reasonable numbers are in those units. I'm as guilty of this as anyone. It does help reduce errors.

When we all gathered to start the ARES project, we agreed that our intuition of typical number values was no longer relevant. Also, we would be working with a lot of 'space' folks that tended to work in the SI system more. So, we decided that the entire ARES development would be done in SI units. We found that pretty quickly, we all developed new intuition basis for new numbers anyway. So it was a non-problem.

From an actual physics point of view, the main challenge was getting good airfoils that would work well. The Reynolds number is extremely low, about equivalent to radio-control gliders, but the Mach number is high. That combination was an area where there had been no previous in-depth research, nothing in technical literature. We were not sure whether to believe the results of our CFD, being so far off from the flow regimes that the codes were developed and tested in. There were very few test facilities that could simulate the flow correctly. We had to develop and gain confidence in our methods as we were designing the airplane. There were certainly many other challenges too, but that is the area I worked on. Lots more to the story.
 
I know this is pretty far from RV related, so if a moderator wants to take it down, I would understand. But I think people would find it interesting.

Everyone here is into experimental aviation...and the biggest space freak here is probably Doug Reeves himself. So no-one is going to take this thread down...or close it. Fascinating stuff.

Kudos to all those involved in the Perseverance mission. This is the current peak of human scientific achievement and a great collaborative effort. Sometimes it's hard to stay positive about humanity but this feat makes my heart sing and gives me hope.

I'm now hoping that as they sequentially test all of the equipment they find that all systems are fully functioning and the little guy is ready to continue the search for life. Go Percy! :D
 
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Being an aircraft designer myself, with several aircraft I have worked that have pushed the envelope to areas we have never gone, this is interesting stuff as I don’t know what I would do if I could not intuitively think through stuff based on past experiences or trust that my tools were giving me the right answers.
I would really like to take that challenge and envy those of you that got to work on this kind of stuff.
Can’t wait for the first flight of Ingenuity. I guess at least a month away before they start flight testing.
I wonder who was their DAR and signed off their airworthiness. FAA has no authority on Mars.
 
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What kind of primer did JPL use on the helicopter?

There, it's an RV thread again...:p

ds
 
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