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James Webb Space Telescope vs SLS



 
 
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  #1  
Old September 12th 19, 12:41 AM posted to sci.space.policy
Alain Fournier[_3_]
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Posts: 414
Default James Webb Space Telescope vs SLS

Both the James Webb Space Telescope and SLS are scheduled for 2021. I
think that SLS has a higher likelihood of schedule slip than JWST
because the purpose of that telescope is to do science and it can't do
that science while on the ground. On the other hand the purpose of SLS
seems to be to save jobs, and it can very well do that with schedule slips.

But maybe that is only bias on my part. What do you people think? I
haven't really kept tabs on science mission schedule slips at NASA. Are
they common?


Alain Fournier
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  #2  
Old September 12th 19, 11:35 AM posted to sci.space.policy
Scott Kozel
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Posts: 33
Default James Webb Space Telescope vs SLS

On Thursday, September 12, 2019 at 1:15:38 AM UTC-4, JF Mezei wrote:
On 2019-09-11 19:41, Alain Fournier wrote:
Both the James Webb Space Telescope and SLS are scheduled for 2021.

https://jwst.nasa.gov/content/about/launch.html
Launch Date
Webb will launch in 2021.
Launch Vehicle

The James Webb Space Telescope will be launched on an Ariane 5 rocket.
The launch vehicle is part of the European contribution to the mission. ...

This isn't just a question of wanting the Telescope up there to do
needed work, it is also a question that Ariann 5 being retired in 2022,
so there is much motivation to get it launched in 2021. (The decision to
laujch on Arianne 5 was taken in 2015 from what I read, so SLS has been
out of the loop for quite some time now).


Maybe Ariane 6 will be available by then.
  #3  
Old September 12th 19, 12:50 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,056
Default James Webb Space Telescope vs SLS

In article ,
says...

On Thursday, September 12, 2019 at 1:15:38 AM UTC-4, JF Mezei wrote:
On 2019-09-11 19:41, Alain Fournier wrote:
Both the James Webb Space Telescope and SLS are scheduled for 2021.

https://jwst.nasa.gov/content/about/launch.html
Launch Date
Webb will launch in 2021.
Launch Vehicle

The James Webb Space Telescope will be launched on an Ariane 5 rocket.
The launch vehicle is part of the European contribution to the mission. ...

This isn't just a question of wanting the Telescope up there to do
needed work, it is also a question that Ariann 5 being retired in 2022,
so there is much motivation to get it launched in 2021. (The decision to
laujch on Arianne 5 was taken in 2015 from what I read, so SLS has been
out of the loop for quite some time now).


Maybe Ariane 6 will be available by then.


Possibly, but NASA isn't going to want to risk a multi-billion dollar
space telescope on a new, not yet fully proven, launch vehicle.

I agree with the position that there is a lot of motivation to get James
Webb Space Telescope launched on time, or at least before Ariane 5 is
completely retired.

Jeff
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These posts do not reflect the opinions of my family, friends,
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  #4  
Old September 14th 19, 01:21 AM posted to sci.space.policy
Greg \(Strider\) Moore
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Posts: 676
Default James Webb Space Telescope vs SLS

"Alain Fournier" wrote in message ...

Both the James Webb Space Telescope and SLS are scheduled for 2021. I think
that SLS has a higher likelihood of schedule slip than JWST because the
purpose of that telescope is to do science and it can't do that science
while on the ground. On the other hand the purpose of SLS seems to be to
save jobs, and it can very well do that with schedule slips.

But maybe that is only bias on my part. What do you people think? I haven't
really kept tabs on science mission schedule slips at NASA. Are they
common?


Alain Fournier

JWST will fly before SLS. It's finally at the point where it's basically
flyable.
And as you said, it's job is to do science, so launching it lets it do its
job.

SLS's job, even if it flies will be done cheaper by other methods.
There's far less pressure on it to fly I think.

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IT Disaster Response -
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  #5  
Old September 15th 19, 03:20 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,056
Default James Webb Space Telescope vs SLS

In article ,
says...

On 2019-09-13 20:21, Greg (Strider) Moore wrote:

SLS's job, even if it flies will be done cheaper by other methods.
There's far less pressure on it to fly I think.



I had been given the impression that one of the SLS flights would be
dedicated to launching something not related to going to the Moon and
that it was the telescope.


This is only partially correct. SLS might be launching the Europa
Clipper. But with the new emphasis on the Artemis program, my guess is
Europa Clipper will be launched on something else (like a Falcon Heavy
with a solid kick stage).

Yet, james Web was "assigned" to Arianne 5 in 2015, so there wouldn't
have been any recent discussions of it going on SLS.


That's because James Webb Space Telescope will be launched on an Ariane
5. The program is so expensive, NASA cut a deal with ESA to launch it,
no doubt in exchange for observation time on the telescope.

parity error in my memory? or is SLS still planned to use one of its
limited rockets to launch a scientific payload to somewhere?


Europa Clipper, not JWST.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #6  
Old September 16th 19, 01:13 AM posted to sci.space.policy
Torbjorn Lindgren
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Posts: 6
Default James Webb Space Telescope vs SLS

Jeff Findley wrote:
In article ,
says...
Yet, james Web was "assigned" to Arianne 5 in 2015, so there wouldn't
have been any recent discussions of it going on SLS.


That's because James Webb Space Telescope will be launched on an Ariane
5. The program is so expensive, NASA cut a deal with ESA to launch it,
no doubt in exchange for observation time on the telescope.


While NASA is the lead agency on JWST the project has AFAIK always
been based on having major contributions from European Space Agency[1]
and the Canadian Space Agency[2].

As an example, there's four main instruments and one of these provided
via NASA, one via ESA and one via CSA with the final being a
cooperation between NASA and ESA. And arguably the FGS (that keeps
JWST on target) that CSA provides is almost an instrument so one could
almost argue they provide "1.5" instruments each :-)

Also listed in the ESA document are the launch and "part of the
operations team" (I'm assuming both before launch and operationally
afterwards).

I expect that NASA is the biggest single contributor, likely even the
majority contributor but it's hard to find any real figures (and those
figures would by necessity be very fuzzy too).


parity error in my memory? or is SLS still planned to use one of its
limited rockets to launch a scientific payload to somewhere?


Europa Clipper, not JWST.


IIRC it's still supposed to be launched by SLS (by senate funding
requirement) because only SLS can send it in a direct trajectory to
Jupiter.

There's been some recent attempts to try to move this to a commercial
launcher instead to save (lots of) money with predictable blow-back
from the senate proponents for SLS.

I think these are merely trial balloons, preparing for if (or perhaps
when) Europa Clipper is getting close to being ready and SLS isn't,
the real discussion can take place because it'll be hard to dismiss as
"mere" speculations.

Apparently an expendable Falcon Heavy with a STAR 48BV? kick-stage can
do it with one gravity assist and Falcon Heavy and Delta IV Heavy can
do it with three gravity assists without a kick stage.

The three gravity assist version is going to be a lot slower than the
SLS direct trajectory (6-7 years vs 2-3 years depending on which
launch window used), the single gravity assist trajectory is clearly
going to be faster than the 3 assist one but I've not seen actual
timings on that trajectory.

1. https://sci.esa.int/web/jwst/-/45728-europe-s-role
2. http://www.asc-csa.gc.ca/eng/satelli...ntribution.asp
  #7  
Old September 16th 19, 11:52 AM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,056
Default James Webb Space Telescope vs SLS

In article , lid says...

Jeff Findley wrote:
In article ,
says...
Yet, james Web was "assigned" to Arianne 5 in 2015, so there wouldn't
have been any recent discussions of it going on SLS.


That's because James Webb Space Telescope will be launched on an Ariane
5. The program is so expensive, NASA cut a deal with ESA to launch it,
no doubt in exchange for observation time on the telescope.


While NASA is the lead agency on JWST the project has AFAIK always
been based on having major contributions from European Space Agency[1]
and the Canadian Space Agency[2].

As an example, there's four main instruments and one of these provided
via NASA, one via ESA and one via CSA with the final being a
cooperation between NASA and ESA. And arguably the FGS (that keeps
JWST on target) that CSA provides is almost an instrument so one could
almost argue they provide "1.5" instruments each :-)

Also listed in the ESA document are the launch and "part of the
operations team" (I'm assuming both before launch and operationally
afterwards).

I expect that NASA is the biggest single contributor, likely even the
majority contributor but it's hard to find any real figures (and those
figures would by necessity be very fuzzy too).


Agreed. This is not unlike how ISS is run, except that with JWST there
aren't as many contributors at an international level (you listed them
all).

https://jwst.nasa.gov/content/meetTheTeam/team.html

parity error in my memory? or is SLS still planned to use one of its
limited rockets to launch a scientific payload to somewhere?


Europa Clipper, not JWST.


IIRC it's still supposed to be launched by SLS (by senate funding
requirement) because only SLS can send it in a direct trajectory to
Jupiter.


True, but the Congress can change its mind.

There's been some recent attempts to try to move this to a commercial
launcher instead to save (lots of) money with predictable blow-back
from the senate proponents for SLS.

I think these are merely trial balloons, preparing for if (or perhaps
when) Europa Clipper is getting close to being ready and SLS isn't,
the real discussion can take place because it'll be hard to dismiss as
"mere" speculations.


More than a trial balloon. The NASA's inspector general has pretty much
recommended commercial launch because it would save the US taxpayers
nearly $1 billion.

NASA inspector general asks Congress for Europa Clipper launch
flexibility by Jeff Foust - August 28, 2019
https://spacenews.com/nasa-inspector...ss-for-europa-
clipper-launch-flexibility/

Apparently an expendable Falcon Heavy with a STAR 48BV? kick-stage can
do it with one gravity assist and Falcon Heavy and Delta IV Heavy can
do it with three gravity assists without a kick stage.

The three gravity assist version is going to be a lot slower than the
SLS direct trajectory (6-7 years vs 2-3 years depending on which
launch window used), the single gravity assist trajectory is clearly
going to be faster than the 3 assist one but I've not seen actual
timings on that trajectory.

1. https://sci.esa.int/web/jwst/-/45728-europe-s-role
2. http://www.asc-csa.gc.ca/eng/satelli...ntribution.asp


The use of Falcon Heavy with a kick stage is surely the way to go.
These kick stages are pretty much "off the shelf" and are considered
part of the payload, as far as the launch vehicle is concerned. There
are many NASA missions which have used such kick stages in the past, so
it's a proven way to provide more velocity for a mission such as this.

Jeff

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All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #8  
Old September 16th 19, 11:55 AM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,056
Default James Webb Space Telescope vs SLS

In article ,
says...

On 2019-09-15 20:13, Torbjorn Lindgren wrote:
There's been some recent attempts to try to move this to a

commercial
launcher instead to save (lots of) money with predictable blow-back
from the senate proponents for SLS.


What difference would it make? They have limited number of SLS flights,
so if one doesn't do the Europa Clipper, it will be used for another
type of unmanned test flight and the same amout of pork $ will be spent.



NASA inspector general asks Congress for Europa Clipper launch
flexibility by Jeff Foust - August 28, 2019
https://spacenews.com/nasa-inspector...ss-for-europa-
clipper-launch-flexibility/

From above:

NASA's inspector general says the agency could save nearly $1
billion if Congress gives it the ability to choose the best
launch vehicle for a mission to Jupiter's moon Europa, rather
than mandating the use of the Space Launch System.

So, the difference is that by using a commercial launch vehicle, the US
taxpayer would save nearly $1 billion. And it would eliminate the
schedule uncertainty inherent with an SLS launch (considering this
Administration's emphasis on Artemis, which "needs" SLS).

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
  #9  
Old September 17th 19, 12:29 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,056
Default James Webb Space Telescope vs SLS

In article ,
says...

On 2019-09-16 06:55, Jeff Findley wrote:

So, the difference is that by using a commercial launch vehicle, the US
taxpayer would save nearly $1 billion. And it would eliminate the
schedule uncertainty inherent with an SLS launch (considering this
Administration's emphasis on Artemis, which "needs" SLS).



No argument about launch uncertainty.

But in terms of saving taxpayers money, I suspect this is accounting PR
to help support buying commercial launch.


It's an acknowledgment from the NASA inspector general that SLS launches
are going to cost $1 billion each. An expendable Falcon Heavy list
price is $150 million. Double that for "NASA specific requirements" and
the off the shelf solid kick stage and you're still at about 1/3 of the
cost of an SLS launch.

But big pictures, NASA has engines for 4 SLS flights. If One of those
flights is not used for Europa Clipper, it will likely be used for
Artemis testing.


SLS flight one is the uncrewed test. The flights after that are
intended to be crewed, excepting a possible Europa Clipper launch.

And even if you were to cancel one of the 4 flights, it won't reduce the
cost of RD that is going to be spent whether you make that 4th flight or
not, and won't save on the cost of engines that have alteady been built.


You're neglecting the costs of the SRBs, core stage, upper stage,
testing, processing, launch, and etc.

So it is more than likely that the $4b spent for 4 flights will remain
$4b for 3, with each flight now costing $1.33b.


Possibly, but you're neglecting the fact that Europa Clipper was to use
SLS long before Aretmis became a thing. This was written into law by
Congress to "justify" SLS before Aretmis was around to "justify" SLS.
The fact that the NASA IG is pointing out is that Europa Clipper never
needed SLS. That was all pork politics.

If the SLS program is more of less fixed cost, then moving Europa
CLipper to a commercial launcher adds the cost of that commercial launch
to the bill sent to taxpayers. (even though the bill to the JWST
department would be much less).


Throwing good money after bad at SLS doesn't make it economical. It's
still 3x as costly for Europa Clipper than a FH with Star kick stage.
SLS will be canceled, sooner or later. The sooner the better, IMHO.

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
 




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