Do space based Scopes require recalibration after launch?

[Stonius]

Just thinking about this in relation to Hubble and the James Webb Space Telescope project.

Sending a telescope into orbit is a hell of a ride. No matter how well you calibrated on the ground, it would likely be out by the time you reach orbit, surely?

Do astronauts perform a final calibration before release? What if it goes out again during use?

Do they use inbuilt servos to calibrate from the ground?

Just curious if anyone knows the answer. Google doesn't seem to care about such trivial matters.:)

Best

Markus

[Zuts]

Hi,

Hubble needed a hardware replacement before it was able to produce what we see today, this involved a shuttle mission.

As for the James Web

quote

'A Solar Orbit. The James Webb Space Telescope will not be in orbit around the Earth, like the Hubble Space Telescope is - it will actually orbit the Sun, 1.5 million kilometers (1 million miles) away from the Earth at what is called the second Lagrange point or L2.'

it will be far too far away to ever be serviced from Earth, so they need to get it right first time.

Cheers
Paul

[Stonius]

So once callibrated (presumably before release) scopes in space never lose their callibration, in spite of temperature changes and movement. Why is that?

[Imme]

Dark matter.......not only does it hold the secret to the creation of the universe, it also likes to fix things when it gets bored......telescopes is one of its favourites.

[AndyG]

Hi Markus,


Perhaps these will help:
https://arxiv.org/pdf/1407.0591.pdf

https://jwst.nasa.gov/mirrors.html#1c

Party on :)

[Lee]

I suspect they are engineered specifically for the conditions expected, with correspondingly large budgets... Perhaps they have motorised components to allow tweaking remotely from Earth? (I'd love to have my newts mirrors motorised...)

[Stonius]

Ah yes - there you go;

Re; the James Webb Scope

"Once in space, getting these mirrors to focus correctly on faraway galaxies is another challenge. Actuators, or tiny mechanical motors, provide the answer to achieving a single perfect focus. The primary mirror segments and secondary mirror are moved by six actuators that are attached to the back of each mirror piece. The primary mirror segments also have an additional actuator at its center that adjusts its curvature. The telescope's tertiary mirror remains stationary."

[The_bluester]

I would imagine they would have some provision for in space collimation/adjustment.

The Hubble servicing/repair mission I would not put in the same context, that was to fit hardware to correct a defect/design issue rather than an adjustment.

[bojan]

Well... they are better designed :P

[sil]

You'd hope, if Webb had same problems as Hubble it'd suck for likelihood of future space scopes. Maybe force moon based missions instead? Wouldn't we be better off with moon based scopes anyway? With bases for servicing/upgrades (go outside pop in a new model ZWO imager?)?

[bojan]

Maybe, in the future... when there will be established Moon base, meaning cheaper stay on the Moon.


I suspect the space telescopes are so far still cheaper to launch then to build Moon base + telescope.