Recent Posts

Pages: [1] 2 3 ... 10 Next
1
Theres a laundry list of problems and risks starship adds. Net gain? Zero? Getting the stuff to mars was never the problem. Getting it OFF OF MARS was always the sticking point. It may be hard to believe, but starship doesn't solve all problems.

It's obvious the descent system is inadequate because it can't deliver an ascent system with enough mass or volume to get the job done. Starship could solve that problem by delivering a better ascent system.
2
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by theinternetftw on Today at 10:54 pm »
I wanted to transcribe Tim Crain's answer about the navigation switchout:

Quote

Tim Crain: It sounds easy in retrospect. We had the Navigation Doppler Lidar (NDL) already plumbed in to the navigation system. So, the three beams on the NDL produce a velocity measurement, as Prasun had talked about. They also produce a range measurement. And we were not using the range measurement, we had just the range rate as a backup to our optical systems. But because it was already plumbed in there, we had to rewrite those, rewrite time tags, into our measurement loader.

But the challenge was, the lasers, we have these two navigation pods on the vehicle, if you can zoom in there. [...] There are these two navigation pods on either side of the vehicle that have cameras. And the laser rangefinders point in the same direction as the cameras. Those angles were optimized for our flight trajectories to give us the best measurements to land softly.

The NDL was under one of these, and its angles were optimized to test the extent of its performance, not necessarily to feed our navigation system, but to test the sensor, because it was a technology development.

So after we figured out we could write the measurements into the laser rangefinder, we had to quickly tell the computer that the laser beams were pointed in different directions. And so there were a number of attitude transformations where it's not in the same location, it's not in the same orientation. And if you've ever seen engineers doing right hand rule transformations, there were a lot of broken wrists, as people were trying to figure out which way is it pointing.

And I will tell you that in normal software development for a spacecraft, this is the kind of thing that would have taken a month. Writing down the math. Cross-checking it with your colleagues. Doing some simple calculations to prove that you think you're right. Putting it into a simulation. Running that simulation 10,000 times. Evaluating the performance. Usually you find an error because you did something in that rotation wrong. And you roll it back and go again.

Our team basically did that in an hour and a half. And it worked.

It was one of the finest pieces of engineering I've ever had a chance to be affiliated with.
3
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by catdlr on Today at 10:52 pm »
I must admit that when I saw the lander for the first time, I though 'wow, that's tall'. It's over 4m high, with a leg span maybe two thirds of that. Any sideways movement vector upon landing would always be risky.

All the previous successful landers always looked... well, squat. Keeping a low centre of gravity and all. With very wide legs. That seemed to make sense. The Apollo landers were about 7m high with a leg span of 9.5m.



Sualdam,  welcome to the forum.  Enjoy your stay here.
4
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by Sualdam on Today at 10:47 pm »
Certainly sounds like a lot of inferences being made in this forum about the reason for the lander to be horizontal at this point.

To be fair, if it had landed in a perfectly vertical vector (as was the design purpose), it wouldn't have tipped over. And the laser system which failed was (presumably) supposed to manage that.

Unless it landed on a large rock and then fell off (which is possible, of course), it is far more likely there was a horizontal vector at the point of touchdown, one or more of the feet snagged (yes, possibly on a rock), and the centre of gravity wasn't low enough to stop it tipping over at whatever velocity the horizontal vector had at that point in time.

Mind you, the moon's surface does seem to be a lot less rocky than people always suggest it is whenever we see surface images from landing sites. It's usually just regolith.

As I commented earlier, IM-1 did seem to be a strange design by being taller than its leg span. Something with such an unusual aspect ratio just had to land perfectly vertically.
5
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by eeergo on Today at 10:44 pm »
Granted, one can attribute EagleCam's "telemetry" tweet to be semantically correct, while people were jumping to conclusions about what it meant (namely, that it'd worked and was sending landing pictures). Also granted, they appear to be attributing to "stale telemetry", whatever that might mean, the fact that they couldn't verify the lander's position and mistakenly stated it was upright when it was, in fact, laying on its side - apparently only noticeable because of the propellant tank's residuals readings, which seems hard to believe when there must be IMUs and other sensors available to at least get an approximation as to whether it's at 90º or not, especially when they were able to detect an 8º roll upon landing.

But there's no way around the fact that they REPEATEDLY tweeted that the lander "remained in excellent health", when that's patently untrue:
- Laser landing system was NOT working, impeded by a hardware safety switch.
- Comms were acting up and led to a major issue with the orbit, plus several hasty replanning steps on the fly.
- Something must have worked so-so to have caused the 8º roll, and the condition that led to the lander falling sideways.
- The lander has a broken leg (!)
- A faceplanted lander on the regolith with antennas pointing down, which hasn't been able to transmit pictures yet because of the difficult comms, and with some solar panels covered is not "in excellent health".

Personally, I saw the treatment of SLIM's bouncy landing as being too harsh, bureaucratically looking at success criteria and not at the exciting happenings on the Moon's surface. It's a great undertaking to achieve a lunar landing in a single piece, no doubt about it. But just as being all sad faces when you just landed somewhat safely is IMO too gloomy, the bombastic treatment of the unconfirmed successes of IM-1 has been quite disappointing in the opposite sense - both from IM and NASA alike. Why is there this allergy towards dispassionately announcing the successes AND failures to the public, matter-of-factly and like the adults they should be? I get it that they're after an ever-fiercer competitive funding landscape (which is perhaps the problem rather than the cure, but that's another matter), but as the $LUNR stock shows, truth can leak out faster than they might manage to conceal it. We'll see about what can be done about the payloads, but as a safe "commercial lunar payload" delivery service, IM-1 is just skirting the line between sporty success and definite failure.
6
NGA Rocket Launching notice and two Space Debris notices (the same notice for two different Navigational Areas):

Maps from the NGA notices. ASDS 630km downrange.
7
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by Zed_Noir on Today at 10:41 pm »
As far as I am concerned. This is mostly a failed first Lunar landing attempt by Intuitive Machines. Will not matter in the long run, if their next (and fiscally doable final) attempt is more successful.

Unlike some posters here. Think the lack of photos and videos during the landing attempt is really bad PR. The days of media people reading out a press release about what happen is long gone. General public interest in a mission requires high quality video presentations of the phases of the mission and the actual event itself to be sustainable, IMO.

Considering how Astrobotic looks right now, IM is considerably better off. At least IM's lander actually made it.

Doesn't matter. The general public will likely not return to watch follow up coverage after the really mediocre landing attempt coverage.

The general public isn't as relevant to IM's future as NASA and IM's shareholders / partners are. <snip>

Lack of interest by the general public is relevant. As that make raising capital in the future for Intuitive Machines harder. Which will likely be done a few more times, as NASA isn't fully funding the development of the Nova-C lander. NASA is just paying a fixed price service contract as  bidded by Intuitive Machines.
8
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by daveglo on Today at 10:38 pm »
Why so much snark about the landing? - they are absolutely in their right to call it succesful in so far as the lander is operational right now. This was not a crash, it wasn't blown to smithereens. It is up there communicating and at full power.
They told us 24 hours ago that the lander was "upright".  It isn't.   Creates doubt.

Good for them to get this lander to and on the Moon.  Much to applaud.  But lander tipped over is not a "success".  No matter how many times they say the word.

 - Ed Kyle


Completely disagree, Ed.  If you have defined mission parameters, and can complete them regardless of the lander's orientation, then it's a success.

And, they kind of get to set those.  So they get to make that call.
9
EUTELSAT 36D Satellite Selected by Airbus to Embark Its Latest Ultra High Frequency Payload

June 30, 2021

Eutelsat Communications’ (Paris:ETL) (Euronext Paris: ETL) EUTELSAT 36D satellite has been selected by Airbus Defence and Space to carry its latest Ultra High Frequency (UHF) payload.

Airbus Defence and Space has already received firm pre-commitments on this payload. Operating in the dedicated 225-400MHz frequency band, the payload will address French governmental applications and other allied governmental applications to support communications over the EMEA region.
...
10
Space Science Coverage / Re: IM-1 Odysseus lunar lander
« Last post by tjchambers on Today at 10:34 pm »
Certainly sounds like a lot of inferences being made in this forum about the reason for the lander to be horizontal at this point.

- Did one leg land on a rock?
- Did it come in with motion horizontally but not level?
- Was it on a slope already and touched down going upslope?
- Any of 100 other possibilities?

I do not pretend to know answers to those questions and lacking access to the telemetry at ground zero, and hopefully pictures of the landing area (which I might add at best will be from one side only), it may be difficult to ascertain.

They are asking the right questions - and seeking answers which they can learn from.

I applaud them for landing at all in a configuration that communicates to earth it is still alive. At least for 9-10 days before the lights go out. None of us is as smart as ALL of us.

Pages: [1] 2 3 ... 10 Next
Advertisement NovaTech
Advertisement Northrop Grumman
Advertisement
Advertisement Margaritaville Beach Resort South Padre Island
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
0