NASA, SpaceX Share Data on Supersonic Retropropulsion | Hacker News Reader

NASA, SpaceX Share Data on Supersonic Retropropulsion

aviationweek.com

91 pointselektropionir24 comments

"The two midwave IR sensors—mounted in a nose pod on the WB-57 and internally on the P-3—were about 60 nm from the rocket when it reignited its engines for supersonic retropropulsion."

They clearly mean Nautical Miles (nm) here, but I did a double-take on my first read through.

Nautical Mile is shortened to NM, or nml.

-DDG

> That produced raw images in which the stage appeared 1 pixel wide and 10 pixels long, but subsequent enhancing by specialists at the Johns Hopkins University Applied Physics Laboratory improved the resolution dramatically.

So, the final resolution was something like... 10x100 pixels? How do you enhance a 1 pixel image? I'm guessing the two aircraft, at two different altitudes, help ... you get 2 pixels instead of 1.

It's (probably) an unstable video, so you take the data from each frame for some large fraction of a second and you can create an image that's somewhere between the total number of available pixels in all the frames and the number in a single frame.

Note: While the spacecraft itself is moving at incredible speeds, the maneuvers themselves are slow enough that several (to many with a high speed camera) images can be combined.

Probably some fun super-resolution (basically, frame stacking with stats!) work. It would trade away some time resolution for spatial resolution, but that could be what they needed.

Maybe they just resample the image to a higher resolution using interpolation. It will not add addittional information but it may make the image easier to analyse and understand. Sometimes an interpolated image will have less error from the actual phenomena than the low resolution version (in the same way that a compressed mp3 is a better reproduction than an uncompressed version of a similar file size).

I had copied that exact text to clipboard to ask the same question. I would guess it's dependent on having video rather than a still but I really don't know.

They know what the stage looks like, they just pasted a high-res photo on it :p

Obligatory "uncrop" clip

https://www.youtube.com/watch?v=JMIHNiR3CP8

SpaceX got a lot of help from NASA, especially in regards to pintle engines[1] and this seems like a great way to pay back that transfer of expertise by moving the ball forward. My assumption (clearly incorrect) was that descent could be managed subsonically as the vertical speed at apogee is 0 but of course that stage has been pushing the second stage into its position and so it travelling down range at several k/s. Presumably you could deploy some sort of upper drag system which would use atmospheric drag to reorient the stage but you still have the fact that its travelling super sonically when you light the engines. I would love to see the CFD simulation of a exhaust nozzle when going that fast backwards! And then you light it off! I really hope that at some point they figure out how to glue a camera on to that stage so we can see what that looks like.

[1] http://blog.nss.org/?p=1900

"Data-sharing deal will help SpaceX land Falcon 9 on Earth and NASA put humans on Mars"

I find the sub-title a bit ironic as (right now) I'd bet that SpaceX astronauts will beat NASA astronauts to Mars.

Dicey bet... NASA has a ton of experience and technology that would help - space suits, working on other planets, driving vehicles around on other planets, etc. As least assuming that the people who know the most about how the Apollo missions worked didn't all retire without leaving any notes.

SpaceX has some funding and a lot of will, but it's hard to say how far they'll be able to go with that, without securing some other massive source of funding.

Seems to me that it wouldn't take much to recruit those people out of NASA if SpaceX actually had a manned project to Mars ready to go.

I'd bet NASA astronauts will go to Mars in a SpaceX rocket bought with NASA money.

Hard to say and kind of irrelevant. The ideal scenario is that they both make it. In fact, if China and Russia could do it, that'd be even better.

It's not irrelevant to me ... I've been a fan of NASA since I was little and clearly remember watching Apollo 11 in awe. I also remember wondering why the Russians could land people on the ground be we had to have a (dangerous) splash down. I guess what I'm saying is that "I'll cheer for all the participants" (and you left out India) but watching the U.S. legislature decimate NASA's funding in combination with NASA's lack of "big feature" projects leaves me wondering about their future.

As an aside, I used to have an E.P. with Kennedy's "New Ocean" speech on one side and key communications between Houston and the spacecraft on the other side as well as a set of cool charts showing the entire flight's trajectory.

Water splashdown is preferable because you don't have to deal with obstacles. Russia simply didn't have the blue-water navy to perform recovery, so they capitalized on their large landmass instead.

I'm curious, why is it better if Russia and China do it first?

I believe @melling implied that it would be better if Russia and China could also get humans to Mars.

The U.S. is just so far ahead in terms of space technology. I am sure one day other countries will catch up, but it is going to be awhile.

It's a matter of will, not necessarily of tech. The US has shown it lacks the will to achieve its former dominance.

Because then space exploration would be a political issue again, and we'd have another space race (hopefully)

This video shows IR footage from one of the planes: https://www.youtube.com/watch?v=_UFjK_CFKgA

I enjoyed Elon's interview on TED. Just when it starts sounding like he's smoking a dream-pipe about recycling rockets, he shows a clip of a test landing. Early days, but it's amazing. I agree with @smoyer, the guys at SpaceX are ninjas, I wouldn't be surprised, because they're making insane advances in a relatively short time-frame. Can't wait to see what they do next.

Reply on news.ycombinator.com