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#1 2021-07-08 09:33:21

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,602

Hubble Space Telescope Replacement

This new topic is offered in recognition of the opening position of OldFart1939 in a debate with GW Johnson.

This topic is available for those who are in favor of discarding the Hubble Space Telescope and replacing it with a new one to do the same work.

The HST is now (about) 30 years of age, and it has recently (July 2021) failed to continue normal operation, and furthermore, it has resisted recovery attempts by NASA engineers.

(th)

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#2 2021-07-08 12:04:42

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,709

Re: Hubble Space Telescope Replacement

We need to build out a network of purpose-built telescopes in Earth or lunar orbit.

1. We need a special purpose telescope to monitor our Sun (probably will be orbiting around the Sun and not readily serviceable unless it has electric propulsion; need to work out if "dark energy" / "dark matter" is simply Hydrogen plasma with an energy state below what we think of as the "ground state").

2. A network of smaller telescopes to monitor the CIS-lunar space region for objects that could potentially impact Earth or provide raw resources that are in short supply here on Earth (such as Platinum group metals).

3. A massive telescope that hunts for habitable planets near our solar system.  Whenever we figure out how to travel faster than light, we will need a very detailed map of nearby objects so that we have some place to go that's worth colonizing.  Even if someone figures out how to break the light barrier tomorrow, we still can't go anywhere without an accurate map, so this is an important "first step".

4. A massive radio telescope that collects data on very distant objects of interest to astronomers.  These are not objects we're likely to ever visit, but in the interest of understanding the broader context of the universe, we still need to study them.

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#3 2021-07-08 12:29:27

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,602

Re: Hubble Space Telescope Replacement

For kbd512 ...

Re Item #1 in Post #2 .... In agreement with your idea, I ** think ** we already have such a telescope.  I ** think ** is is located at L1

Agree with 2, 3 and 4 ...

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#4 2021-07-08 16:12:11

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,709

Re: Hubble Space Telescope Replacement

Reposting this here, at the request of tahanson43206, even though I think a Mars colonization ship requires a giant gas station with a variety of liquid consumables available for on-orbit replenishment:


tahanson43206,

If Starship can deploy a telescope that's even larger than the James Webb, then why wouldn't we build a bigger telescope or return Hubble to Earth for major repairs, and then redeploy it after we've thoroughly upgraded every major system?

$4M for a pair of launches seems like a pittance to pay for the data that Hubble provides.  We could re-grind the lenses / mirrors so that software correction of the received images is no longer required, as well as substantially upgrading all of its imaging and control electronics.  I think repair and re-launch of a failing telescope would be a good test mission to begin proving the operational reliability of Starship.

If there's a "first mega structure" that we build in space, why wouldn't it be a propellant / refueling depot?

All of these ships will require propellants and water, so I think we should have a purpose-built, free-flying propellant depot to replenish Starships and colonization ships with propellants.  It would be beneficial to be able to store the propellant in orbit at a powered facility that can keep cryogenic propellants cold.  If all of the propellants to go somewhere else are stored and available for use before humans are sent into space, then there's no risk of them having to return to Earth, no risk of them smacking into the tanker ships during refueling operations, no having to hang out in space and sit through multiple refueling missions, and all of the consumables expended while waiting don't have to be.  I think a mission away from Earth should be a "load and go" proposition for Starships and colonization ships.  Here on Earth, we load propellant prior to or after loading people, but it's all done as part of a single operation.  NASA uses commercial contractors that send tanker trucks to deliver ultra-pure LH2 to their storage tanks at KSC, but then the LOX/LH2 is loaded into STS or SLS in about an hour.  In other words, they don't have a conga line of tanker trucks roll up next to the giant rocket to deliver propellant.

If we combine the propellant depot with air scoops that collect O2 and N2 from the upper atmosphere, then we only have to supply the fuel using a chemical rocket sent from Earth.  In theory, we only have to supply LH2, or LH2 and CO2, if the in-space stage uses LCH4.  H2O and CO2 are indefinitely storable at non-cryogenic temperatures.  However, LH2 is much lighter than water, therefore less costly to transport, and could be burned with the collected O2 or combined with the O2 to produce potable water.

If you're a foreign space agency, then you can pay to use the gas station for your science missions.  Instead of being subjected to severe payload mass restrictions dictated by the remaining propellant in an upper stage, you can refuel your upper stage at the gas station, so you can use the upper stage to get into orbit, refuel at the gas station, pay for your gas, and leave with a full tank.  That way, you can afford to devote more mass to the mission payload and possibly use less expensive or more durable metals in your satellite or rover, like steel vs Aluminum.  We can offer AF-M315E (less toxic Hydrazine replacement for satellites), LOX, LH2, LNG, LPG, LN2 (pressurant / cold gas thruster monopropellant), LNH3 (radiator / heat exchange systems), LCO (low cost fuel to provide lots of thrust), LCO2 (also for heat exchange), H2O (for crewed missions), and LAr (Liquid Argon for electric propulsion).  You could also do on-orbit replenishment of propellants for communications and weather satellites.  When they run low on propellant, rather than becoming space junk, they instead go to the gas station, refuel, and re-boost into their nominal orbit.  This will economize on the use of propellants required to maintain space infrastructure by not having to deliver both the satellite and its propellants to orbit, or in practice, delivering a brand new fully fueled satellite from the surface of the Earth.

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#5 2021-07-08 17:27:46

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,768
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Re: Hubble Space Telescope Replacement

kbd512 wrote:

$4M for a pair of launches seems like a pittance to pay for the data that Hubble provides.  We could re-grind the lenses / mirrors so that software correction of the received images is no longer required, as well as substantially upgrading all of its imaging and control electronics.  I think repair and re-launch of a failing telescope would be a good test mission to begin proving the operational reliability of Starship.

I find it jaw-dropping amazing that we're talking about that price! In an interview in November 2019, Elon estimated $2 million per launch. However, that's based on 1,000 Starships. In an interview with reddit in March 2020, he said the goal is $5 million per launch this year. And that's cost to SpaceX, not price to customer. Still, Delta IV Heavy costs US$350 million per launch, which is the only other launch vehicle capable of launching Hubble. And it doesn't have capacity to return it to Earth! SLS block 1 could do it, but it hasn't launched yet, and it's estimated at US$2 billion per launch! Even if Starship costs $5 million per launch, $10 million is cheap to keep Hubble in space.

That said, my idea to service Hubble didn't require any in-space infrastructure. Just carry tools and parts in the trunk of Dragon. It might be possible with Falcon 9 if the launch vehicle is expended. Because Hubble has dropped into a lower orbit. To recover boosters would require Falcon Heavy. Down side is it requires a small robot arm as foot restraint for the astronaut. There would be no way to return that to Earth intact. So it would be de-orbited with the trunk when Dragon returns. Falcon 9 costs US$62 million per launch with a new booster, US$50 million for a used one. But is that price with the booster recovered? And how much for Dragon?

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#6 2021-07-08 20:14:29

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: Hubble Space Telescope Replacement

The question of engines is one of vibrations and fuel contaminant on the lenses...

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#7 2021-07-08 20:40:43

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,768
Website

Re: Hubble Space Telescope Replacement

Shuttle was able to rendezvous with Hubble. And Shuttle used MMH/N2O4 for RCS thrusters. Dragon uses the same, but it's smaller.

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#8 2021-07-09 18:04:31

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: Hubble Space Telescope Replacement

The telescope was not active in use and had the shutters closed to keep contamination out.
The Hubble could not be active in its role while a set of engines on the unit were firing.

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#9 2021-07-09 21:25:43

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,768
Website

Re: Hubble Space Telescope Replacement

SpaceNut,
You realize I suggested a Dragon service mission. Not a station left permanently near Hubble.

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#10 2021-07-10 08:13:39

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 23,342

Re: Hubble Space Telescope Replacement

Yes I see and while the computer is down the doors to the lens system can not close so caution needs to be taken under even a temporary repair operation occurs.

Since Hubble is in need of such an extensive repair I am wonder if a direct attachment (aka SM) unit with all of the replacements contained to work with a seperate computer might be a better option as the unit parts will wear out eventually once more. About all that we need from the original unit is the mirror assembly/ housing and connection points to connect the controls into.

So sort of combining a shuttle bay and a cygnus design to allow for like capability to do the service.

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#11 2021-07-10 15:22:04

GW Johnson
Member
From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 4,621
Website

Re: Hubble Space Telescope Replacement

Whether Hubble is replaced or repaired is not the most important issue.  The more important issue is an on-orbit capability to repair and upgrade satellites.  We had that with space shuttle,  although it was only used on Hubble. 

We no longer have such a capability,  but we could have one again.  And it needs to be used for more than just Hubble. 

My posts elsewhere on this topic,  and on my "exrocketman" site,  explain how this could be done,  what is required to do it,  and that it could be a lot more cost-effective than what we had based on space shuttle.

More important than the satellite repair and upgrade capability is actually the launching of several satellite telescopes that we currently do not have.  Kbd512 hit on this in post #2 above.  His point #2 in that posting is related to planetary defense against impacting celestial objects,  which is actually the very most important reason to have a space program at all,  manned or unmanned. 

Kbd512 mentioned cis-lunar space for these satellites,  but the real place to put them is in solar orbit,  nearer the distance of Venus from the sun.  That way,  they always look outward,  away from the sun,  and can see objects approaching Earth from more sunward directions.  Nothing on Earth or in cis-lunar space can do that.

The most successful means to search for these objects would be infrared,  not visible.  Most of these objects are about the color of a piece of charcoal,  and quite nonreflective.  But they are warmer than deep space,  being warmed by the sun.  IR is the best way to find them.  Then you use visible for the spectra stuff,  and radar for the tracking.  So we are looking at perhaps 3 IR detection satellites spaced around a solar orbit about 60 or 70 million miles from the sun.  The visible and radar can be mostly here on Earth.  But NOT 100% of it!

I put these notions up,  with good data-based justifications as to why,  in an "exrocketman" article dated 30 August 2020 titled "Asteroid Threats" which builds upon earlier articles I posted.  My conclusions about this have not really changed since I attended the 2009 planetary defense conference in Granada,  Spain.  We've found more extinction event objects,  but not very many city-buster objects,  since then.  Some,  but nowhere near enough.  And the track record of detections in time to support civil defense evacuations is very poor indeed.

The Planetary Society under Bill Nye has more recently come to pretty much the same conclusions,  justified by pretty much the same data and reasoning.  Their June issue of "The Planetary Report" is almost entirely devoted to the planetary defense topic.  In particular,  I would point out in that issue the article "Risky Business" by Jason Davis. 

It's not just detection,  there have to be missions that determine how much spall you get from impacts vs asteroid type,  and how hard you can push on an asteroid without it breaking up vs asteroid type.  And these things are proving to be far more diverse than just types C,  S,  and M.  Some of that is one-way unmanned stuff,  and some of it will require that men actually go there and experiment with deflection approaches.  There is no way around that.

Which in turn means that we need better rockets,  and better manned spacecraft capable of years-long missions without doing microgravity harm,  radiation exposure harm,  or too-tight confinement harm. 

Anything capable of taking men safely to near-Earth asteroids is more-than-capable of taking men to Mars.  So these are NOT competing mission objectives;  they are in fact quite complementary.  And,  launching the detection satellites into solar orbit,  plus a satellite repair capability in Earth orbit,  all this is complementary stuff,  too.  If you can do the one,  you can do the other,  and with a lot of the same hardware.

I suggest y'all go look at the sources I just cited.  It might surprise you. 

GW

Last edited by GW Johnson (2021-07-10 15:48:07)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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