IM-1 Odysseus lunar lander

[LouScheffer]

IIRC (there was a discussion about this in one of the DSN threads) it's mainly because it's significantly cheaper to build smaller dishes and NASA's plan to upgrade the DSN is way overbudget. So they are focusing on the smaller dishes first.

I believe (willing to be corrected) that one of the key issues is that the smaller dishes are commercially available, whereas a larger dish would have to be custom-built. In addition, I would not say that the plan for upgrading DSN is "overbudget"--the agency has never adequately funded their requirements because infrastructure always gets neglected.

The smaller dishes are not off the shelf, but General Dynamics has built more than 10 of them for DSN, and continues to build more.  So the knowledge of how to build them is current.

Also the old 70 meters are expensive to maintain.  Not only are they old and wearing out, they are of a design where all the transmitters, and cryogenic receivers, are up high at the focus and swing around when the antenna moves.  The new antennas reflect the focus into the basement ("beam waveguide") so all the fancy electronics are at ground level and indoors, making maintenance and upgrades much simpler.  As JPL says:

The new antennas, known as "beam wave guide" antennas, can be used more flexibly, allowing the network to operate on several different frequency bands within the same antenna. Their electronic equipment is more accessible, making maintenance easier and less costly. The new antennas also can receive higher-frequency, wider-bandwidth signals known as the "Ka band." This band, required for new NASA missions approved after 2009, allows the newer antennas to carry more data than the older ones.

For receiving, when you really need the sensitivity you can array 34 meter dishes.  But for transmitting, nothing beats a giant honking transmitter (500 kW) on a giant honking dish (70 meter).  That's why they are needed for commanding really far away missions (like Voyager), planetary radar, and emergency commanding of spacecraft during anomalies when those craft can only use their low-gain antennas.   So I suspect that although NASA would love to retire those old expensive dishes, they will be stuck with them for quite a while.

[spacexplorer]

Next time you'll get a plane you will understand why this landing was a failure. Anyway, we have a failed landing followed

You are not really comparing a flight on a commercial regularly scheduled flight to a first time landing on the moon by this company with this vehicle? (Yes some of the issues were mistakes, etc. but you can't use the same rules to qualify two vastly different things) (as already written by others earlier), what's considered a failure for your flight does not mean a failure here.

[/quote]
OF COURSE I meant: when in your next flight your plane will land so hard that it will crash its landing gear and bend the fuselage making some exits unusable, but you will survive just because it didn't catch fire, you will understand why what happened to im-1 was not  "landing successfully and being a great success" but "crash on the moon but luckily survive by unbelievable coincidence and be able to continue the mission".
I'm glad it survived, but given the root causes of the  issues , and  how the issues were described and managed, I will never purchase a flight with IM for my payloads. But I would accept if they pay me for giving them my payloads for testing.

[spacexplorer]

IIRC (there was a discussion about this in one of the DSN threads) it's mainly because it's significantly cheaper to build smaller dishes and NASA's plan to upgrade the DSN is way overbudget. So they are focusing on the smaller dishes first.

I believe (willing to be corrected) that one of the key issues is that the smaller dishes are commercially available, whereas a larger dish would have to be custom-built. In addition, I would not say that the plan for upgrading DSN is "overbudget"--the agency has never adequately funded their requirements because infrastructure always gets neglected.

The smaller dishes are not off the shelf, but General Dynamics has built more than 10 of them for DSN, and continues to build more.  So the knowledge of how to build them is current.

Also the old 70 meters are expensive to maintain. 

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

[Blackstar]

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

There are reasons why lasercom probably won't work past Jupiter distance.

[Blackstar]

are not off the shelf, but General Dynamics has built more than 10 of them for DSN, and continues to build more.  So the knowledge of how to build them is current.

I have vague memory of hearing that at least part of the smaller dishes is off-the-shelf technology. Maybe some of the internal stuff is common to other dishes used commercially?

[DanClemmensen]

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

There are reasons why lasercom probably won't work past Jupiter distance.

What are those reasons?

[Blackstar]

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

There are reasons why lasercom probably won't work past Jupiter distance.

What are those reasons?

Pointing accuracy. But I don't know. You can google all this stuff. I have not heard a detailed DSN briefing in a few years.

This article points about using laser comm at very far distances, but I believe I heard Ralph McNutt (mentioned in the article) say that it gets dicey around Jupiter distance.

https://www.centauri-dreams.org/2022/12/07/interstellar-communications-the-pointing-problem/

[LouScheffer]

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

There are reasons why lasercom probably won't work past Jupiter distance.

What are those reasons?

There is a discussion about this in the Uranus orbiter and probe thread, some of which makes sense.  Basically existing optical comms (as being tested on Psyche) go out to about Jupiter.   There appear to be no physics reasons it can't work at outer planets, but it would take work to develop.  For example, Psyche knows where to point the down-beam by following an up-beam sent from Earth.  To do this at the outer planets is impractical, so you need blind pointing.  But spacecraft don't usually have that degree of stability or pointing accuracy, so you need a special platform.  You need big optical telescopes for receiving, but these are all being used, so you'd need new ones specialized for the job.  And so on.)

[LouScheffer]

are not off the shelf, but General Dynamics has built more than 10 of them for DSN, and continues to build more.  So the knowledge of how to build them is current.

I have vague memory of hearing that at least part of the smaller dishes is off-the-shelf technology. Maybe some of the internal stuff is common to other dishes used commercially?

JPL also considered large arrays of 6 or 12 meter dishes.  These would be off the shelf.  Maybe that's what you were thinking of?

One basic tradeoff is receivers vs dishes.  For lots of small antennas, the collecting area is cheap, but you need lots of cryogenic receivers, one per dish.   For a few big antennas, you need only a few receivers.

Another tradeoff, and maybe the big one for JPL, is commanding.  There is no existing technology for arrayed transmitters, which is a harder problem than arrayed receivers.  So if you need bigger dishes anyway for commanding and navigation, may as well use them for reception as well.

[jimvela]

are not off the shelf, but General Dynamics has built more than 10 of them for DSN, and continues to build more.  So the knowledge of how to build them is current.

I have vague memory of hearing that at least part of the smaller dishes is off-the-shelf technology. Maybe some of the internal stuff is common to other dishes used commercially?

JPL also considered large arrays of 6 or 12 meter dishes.  These would be off the shelf.  Maybe that's what you were thinking of?

One basic tradeoff is receivers vs dishes.  For lots of small antennas, the collecting area is cheap, but you need lots of cryogenic receivers, one per dish.   For a few big antennas, you need only a few receivers.

Another tradeoff, and maybe the big one for JPL, is commanding.  There is no existing technology for arrayed transmitters, which is a harder problem than arrayed receivers.  So if you need bigger dishes anyway for commanding and navigation, may as well use them for reception as well.

We're straying just a bit from the core IM-1 topic, but since it's still relevant to this style of mission I'll add this-

Not every contact needs to be a command (uplink) pass.  Arrays of less expensive smaller dishes can still have high utility for scheduled downlink-only passes.

If the link to closes with these less expensive options you get potential benefits of additional downlink time. 
Deep space missions are constrained by available downlink time much more than uplink time.

[Svetoslav]

IM announces mission success. Some interesting numbers here - 144 hours of work, 350 MB data gathered.

https://investors.intuitivemachines.com/news-releases/news-release-details/intuitive-machines-historic-im-1-mission-success-american

[Comga]

IM announces mission success. Some interesting numbers here - 144 hours of work, 350 MB data gathered.

https://investors.intuitivemachines.com/news-releases/news-release-details/intuitive-machines-historic-im-1-mission-success-american

To be precise, 144 hours of surface operations was a goal that OM-1 exceeded before it suspended operations.

In passing they mentioned “NASA’s $93B Artemis Campaign”
That’s a really big number

OM-1 Fraction of Artemis cost: 0.2%
Fraction of data from the Moon to date: 100%
(Yes, that is contrived.)

Remember, this is a note to investors.  If there is a place for the most upbeat perspective it is there, but IMO they have a great accomplishment to report.


edit: decimal place   thanks brussell

[ChrisC]

IM announces mission success. Some interesting numbers here - 144 hours of work, 350 MB data gathered.
https://investors.intuitivemachines.com/news-releases/news-release-details/intuitive-machines-historic-im-1-mission-success-american

Capture of what they wrote there.  PDF is attached below.

Intuitive Machines Historic IM-1 Mission Success: American Ingenuity Never Gives Up
February 29, 2024 at 6:22 PM EST

HOUSTON, Feb. 29, 2024 (GLOBE NEWSWIRE) -- Intuitive Machines, Inc. (Nasdaq: LUNR, LUNRW) (“Intuitive Machines”) (“Company”), a leading space exploration, infrastructure, and services company, today announced the completion of science and data transmission for all NASA and commercial payloads onboard Odysseus, the Nova-C class lunar lander, after the successful February 22 soft landing on the south pole region of the Moon.

Intuitive Machines CEO Steve Altemus said, “Spaceflight’s unique challenges are conquered on Earth but mastered in space. Our now proven robust lunar program, a national asset, feeds directly into our second and third missions. This success drives our relentless pursuit of performance excellence to benefit the entire industry.”

Intuitive Machines achieved these marquee accomplishments in the Company’s first attempt to land on the Moon:

- Successfully soft-landed the Company’s Nova-C class lunar lander, Odysseus, on the Moon, marking the United States’ first lunar landing in over 50 years since Apollo 17
- Validated the performance of the Company’s proprietary liquid methane and liquid oxygen propulsion system through the first-ever deep space ignition, followed by multiple restarts, repeatedly providing successful spacecraft maneuvers
- Became the first commercial-sector company and NASA CLPS (Commercial Lunar Payload Services) provider to successfully land and transmit scientific data to and from the Moon
- Landed Odysseus, farther south than any vehicle in the world has ever soft-landed on the Moon, which we believe is significant given NASA’s $93B Artemis Campaign is targeting the region for human missions
- Traveled over 600,000 miles and softly landed less than one mile from its intended Malapert A landing region
- Transmitted over 350 megabytes of science and engineering data, which was collected across all payloads; NASA confirms mission success
- Exceeded one of the mission objectives to operate 144 hours on the lunar surface and entered standby mode on February 29, 2024, as we await two to three weeks for the next lunar day and a potential for Odysseus’ revival
- Fundamentally disrupted the economics of landing on the Moon through a fixed-price performance contract, demonstrating unprecedented economics and efficiency to commercial customers and NASA

Accomplishing the IM-1 mission required Intuitive Machines to integrate on a global scale. Radio astronomy dishes spread across a dozen countries, international hardware providers, and the strength of the United States domestic supply chain across more than 50 congressional districts were paramount in the IM-1 mission success.

Mr. Altemus continued, “Before this mission, we had an absolute sense of humility and relied on our technical excellence and years of experience to triumph and persevere throughout all the challenges we faced during the mission. Following our unequivocal success, I am emboldened for the future of the U.S. and international lunar economy and Intuitive Machines' future as we believe we can win, execute, and pioneer the future of the cislunar market.”

[catdlr]

https://twitter.com/CrainTim/status/1763655455564242952

The displays in Nova Control turn purple when they lose telemetry.  As the spectral power from Odie's radios faded to the noise, the floor and all the displays turned purple, we played Purple Rain and said goodnight.  We'll look for Odie with the dawn (like Gandalf). #adlunam

[CuddlyRocket]

When they realized the laser rangefinder was not working and they needed to find a solution, why did they push the landing by only one orbit, couldn't they have pushed it off several orbits to give themselves more time? what was the constraint? (Perhaps they were that low on propellant that another orbit would mean not enough propellant to land, but I highly doubt this, I hope there's a better explanation I missed somewhere)

On CNN, Bill Nelson said that they could have done only one more orbit and still land. He didn't say why. 

I believe it's because the Moon is rotating under the orbit (about 3 degrees per day) moving the landing site away from the orbital path.

[Don2]

Very interesting! I wonder if that is why JPL DSN is looking at building more small dishes and running them as a array to get good reception of weak signals vs the very large dishes that are due to be retired.

People have studied how to get the lowest cost per square meter of receiving area. 18 meter diameter works out to be the cheapest. They can be arrayed together to simulate a larger diameter dish.

The ngVLA is going to build about 200 18m antennae. When that production line gets going they should be quite cheap.

[Don2]

Will the recent success of laser communication make the Big Dishes obsolete one day? Can laser be used to communicate with missions to external planets? How big should the ground based stuff  be?

No, because lasers won't go through cloud cover. I think they have somewhat oversold the benefits of optical communications. Laser comm works best at night. The data rate is lower in daytime. Optical also requires precise pointing, and is not going to work if the spacecraft is tumbling or has fallen over. IM-1 had multiple antennae sending signals in different directions.

The current optical experiment is using a 5m telescope as a receiver. They would like a network of 8 to 12m telescopes as receivers. Those would probably cost about $120 million each, versus $60 million for a 34m radio antenna or $40 million for four 18m antennae. However, they may be able to use Cerenkov type telescopes, which provide a large diameter at a very low price.

More about that in this thread:
https://forum.nasaspaceflight.com/index.php?topic=56579.0

The current pointing system won't work for Uranus. I'm not sure about Saturn. One issue is that it takes a long time for light to make the trip and the Earth moves in its orbit, so they have to point ahead of the earth. Using an image of the Earth might work for pointing at Uranus, but that likely has it's own challenges.

In my opinion the biggest advantage of optical is that it enables a one to two order of magnitude improvement in distance measurements, and hence in solar system gravitational fields.

[jimvela]

The current pointing system won't work for Uranus. I'm not sure about Saturn. One issue is that it takes a long time for light to make the trip and the Earth moves in its orbit, so they have to point ahead of the earth. Using an image of the Earth might work for pointing at Uranus, but that likely has it's own challenges.

Pointing for deep space telecom is performed using ephemeris products for the spacecraft and ground station(s).
No one does or will use an "image of the Earth." for this activity.

The pointing limitation at great distances comes down to the pointing capabilities of the spacecraft and the ground station, not the ability to know where to point.

[Steven Pietrobon]

So the change in height of the cg is deltaH = (1.268 - 1) = 0.268 units. The potential energy is (m g DeltaH). Tipping over occurs if this potential energy is less than the sideways kinetic energy. Solving for v, the tipping limit is v>Sqrt(2 g DeltaH)

For g = 9.807 m/s˛ on Earth and 1.625 m/s˛ on the Moon, this gives tipping speeds of only 2.3 m/s on Earth and 0.9 m/s on the Moon for the IM-1 lander!

I forgot to scale the deltaH by the actual dimensions of the vehicle! The width of the landing legs is 4.6 m.

https://www.cnbc.com/2024/02/22/intuitive-machines-lunr-im-1-moon-landing-for-nasa.html

With six legs, this gives a 360/6 = 60° spacing between the legs. Thus, the minimum radius of the landing legs is (4.6/2)*cos(60/2) = 1.992 m. Dr. Metzger showed the normalised radius as 0.78. Thus, the actual deltaH is 0.268*1.992/0.78 = 0.684 m, which gives a tip over speed of 1.17*sqrt(g) or 3.66 m/s on Earth and 1.49 m/s on the Moon. My apologies to IM for the wrong calculation. Still, these speeds are pretty low. The Lunar tip over speed is a little above walking speed on Earth.

[matthewkantar]

So the change in height of the cg is deltaH = (1.268 - 1) = 0.268 units. The potential energy is (m g DeltaH). Tipping over occurs if this potential energy is less than the sideways kinetic energy. Solving for v, the tipping limit is v>Sqrt(2 g DeltaH)

For g = 9.807 m/s˛ on Earth and 1.625 m/s˛ on the Moon, this gives tipping speeds of only 2.3 m/s on Earth and 0.9 m/s on the Moon for the IM-1 lander!

I forgot to scale the deltaH by the actual dimensions of the vehicle! The width of the landing legs is 4.6 m.

https://www.cnbc.com/2024/02/22/intuitive-machines-lunr-im-1-moon-landing-for-nasa.html

With six legs, this gives a 360/6 = 60° spacing between the legs. Thus, the minimum radius of the landing legs is (4.6/2)*cos(60/2) = 1.992 m. Dr. Metzger showed the normalised radius as 0.78. Thus, the actual deltaH is 0.268*1.992/0.78 = 0.684 m, which gives a tip over speed of 1.17*sqrt(g) or 3.66 m/s on Earth and 1.49 m/s on the Moon. My apologies to IM for the wrong calculation. Still, these speeds are pretty low (the Lunar tip over speed is equal to walking speed on Earth) and so in hindsight its not surprising the vehicle tipped over. Hopefully, future vehicles will have a lower centre of mass and wider legs to prevent this problem.

Hopefully the lens cap will be off the LIDAR!