SpaceX Falcon 9 : PAZ & Microsat 2a/2b : SLC-4E : Feb 22, 2018 : DISCUSSION

[aero]

Saw this on the web this morning.

https://www.cnet.com/news/spacex-falcon-9-internet-satellites-sunday-launch/#ftag=CAD590a51e

First SpaceX internet satellites now set to launch Wednesday

Elon Musk's rocket company has been working on getting satellite broadband off the ground for years. Now the Falcon 9 is set to launch the first test.

But then, the information in the article may have been gleaned from this thread, so ...

[Robotbeat]

Updated presskit was just posted here.

Current launch date: Feb 21st 14:17 UTC
Backup launch date: Feb 22nd 14:17 UTC

No reference to the MicroSat-2a and MicroSat-2b satellites on the press-kit.

https://forum.nasaspaceflight.com/index.php?topic=42485.msg1789360#msg1789360

For those who don't want to click through just to see a short statement:

I see the press kit is out (see update thread) - and not a single mention of the SpaceX prototype satellites. The are really trying to play this close to the vest. I wonder how much or little they will say about in the webcast...

PAZ is the primary mission.
Those piggyback payloads have a lot riding on them. No need to reveal anything to the competition if you don't have to.

[cscott]

Official:
https://twitter.com/SpaceX/status/964937069901447168

Team at Vandenberg is taking additional time to perform final checkouts of upgraded fairing. Payload and vehicle remain healthy. Due to mission requirements, now targeting February 21 launch of PAZ.

Upgraded fairing?

Well this leads us to believe no one wanted upgraded fairing on first flight so they must told these guys, your getting sweet deal on this launch that we going to try some new things out....

If this is the case, I wonder why they did not put the new fairing on FH demo?

Who's to say they didn't?  They could have learned something from the FH demo flight that led to extra checks on Paz.

Also: perhaps stripping the legs gives some extra margin that allows them to fly a slightly heavier fairing on block 4.  This was a theory mooted about for the previous Vandenberg flight; never really resolved one way or the other.  (Mr. Steven was not complete for that earlier mission, it now appears.)

[Barrie]

I hesitate to ask, but are the fairing checks for the assurance of the primary mission, or the fairing recovery effort?

[Inoeth]

I hesitate to ask, but are the fairing checks for the assurance of the primary mission, or the fairing recovery effort?

It's not known why they're checking the fairing - tho since it's brand new, it's probably a little bit of both... they want to make sure everything's looking good, that it'll open properly and that the recovery hardware is all testing out good...

It's been weird that SpaceX, despite now having 3 launch pads, is moving very slowly with launches right now compared to last year... I thought we'd be at 3 launches a month, but it's more like one a month... and they just delayed a bunch of launches by a couple days or weeks...

[rockets4life97]

I thought we'd be at 3 launches a month, but it's more like one a month...

In the last 3 months we have:
* December: 2 launches
* January: 2 launches
* February: 1 launch (and 2 scheduled)

March has 2 launches scheduled as well. So, more like 2 launches a month plus Falcon Heavy.

Remember Block V is rolling out. I expect the pace will pick up after that.

It may be more like 2 pads at the moment as well, if 39A is down to add the crew access arm. This could be why missions thought to be launching from 39A were shifted to 40. I'm thinking of CRS-14 and TESS in particular.

[AncientU]

I thought we'd be at 3 launches a month, but it's more like one a month...

In the last 3 months we have:
* December: 2 launches
* January: 2 launches
* February: 1 launch (and 2 scheduled)

March has 2 launches scheduled as well. So, more like 2 launches a month plus Falcon Heavy.

Remember Block V is rolling out. I expect the pace will pick up after that.

It may be more like 2 pads at the moment as well, if 39A is down to add the crew access arm. This could be why missions thought to be launching from 39A were shifted to 40. I'm thinking of CRS-14 and TESS in particular.

2 per month for first half of 2018 and 3 per month for remainder gets to 30 launches. 
Just about right.  (But we can still want more...)

[Roy_H]

So why is a 400kg satellite called a microsat? How would you describe a cubesat? How big does a satellite have to be to be described as small, medium and large?

[Jarnis]

So why is a 400kg satellite called a microsat? How would you describe a cubesat? How big does a satellite have to be to be described as small, medium and large?

cubesats are "nanosats". Dunno if there are official weight classes, but 400kg is basically never a primary payload, so microsat seems legit.

[meekGee]

I thought we'd be at 3 launches a month, but it's more like one a month...

In the last 3 months we have:
* December: 2 launches
* January: 2 launches
* February: 1 launch (and 2 scheduled)

March has 2 launches scheduled as well. So, more like 2 launches a month plus Falcon Heavy.

Remember Block V is rolling out. I expect the pace will pick up after that.

It may be more like 2 pads at the moment as well, if 39A is down to add the crew access arm. This could be why missions thought to be launching from 39A were shifted to 40. I'm thinking of CRS-14 and TESS in particular.

2 per month for first half of 2018 and 3 per month for remainder gets to 30 launches. 
Just about right.  (But we can still want more...)

And while the manifest is still large, currently growth in SpaceX launch rate only comes at the expense of other launchers...  And some of it already occurred, so it'd diminishing returns...

What's next is growth in the market, but we all knew this will lag, and (not unexpectedly) seems like it will be headed by SpaceX itself as its own customer.

[meekGee]

So why is a 400kg satellite called a microsat? How would you describe a cubesat? How big does a satellite have to be to be described as small, medium and large?

cubesats are "nanosats". Dunno if there are official weight classes, but 400kg is basically never a primary payload, so microsat seems legit.

I'd have gone with milliSat...   

The only reason they went straight to micro and nano is that those are the buzz words in what the rest of the world calls "high tech"....

But in normal volumetric measures, you down 1 OOM in linear length, you go down one prefix in the unit... Liter, mL, uL, nL, pL...

So a 10 m satellite, a 1 m mSat (like we have here), a 10 cm uSat (a.k.a cubeSat), a 1 cm nSat (there have been proposals)

But hey, this is marketing, so whatever works.

[deruch]

Where is the info on the mass of the MicroSats coming from?  I think we've only seen info on what was planned for the SpaceX constellation and comments that these would be prototype vehicles for testing purposes.  But nothing that they would be of such high fidelity to be close to the mass of the actual constellation sats.  Just that they would be able to test the required hardware.  I guess I had been envisioning something closer to 50-100kg max.  And very possibly smaller.

[Skyrocket]

Where is the info on the mass of the MicroSats coming from?  I think we've only seen info on what was planned for the SpaceX constellation and comments that these would be prototype vehicles for testing purposes.  But nothing that they would be of such high fidelity to be close to the mass of the actual constellation sats.  Just that they would be able to test the required hardware.  I guess I had been envisioning something closer to 50-100kg max.  And very possibly smaller.

From the FCC filing, Purpose of Experiment ( https://apps.fcc.gov/els/GetAtt.html?id=185534&x=. )

The primary structure for the Microsat-2a and -2b test spacecraft will be a box design measuring 1.1m x 0.7m x 0.7m and carries the spacecraft flight computer, power system components, attitude determination and control components, propulsion components, GPS receiver, and broadband, telemetry, and command receivers and transmitters. The primary bus is mounted on the payload truss system, which also carries communications panels, inter-satellite optical link transmitters and receivers, star trackers, and a telemetry antenna. There are two 2x8 meter solar panels. Each demonstration spacecraft has a total mass of approximately 400kg

[gongora]

Where is the info on the mass of the MicroSats coming from?  I think we've only seen info on what was planned for the SpaceX constellation and comments that these would be prototype vehicles for testing purposes.  But nothing that they would be of such high fidelity to be close to the mass of the actual constellation sats.  Just that they would be able to test the required hardware.  I guess I had been envisioning something closer to 50-100kg max.  And very possibly smaller.

The Microsat 1a/1b sats that they didn't end up launching were along the lines of what you're envisioning.  They were very simple, no propulsion, just testing some subsystems.  The Microsat 2a/2b sats are much more functional.

[speedevil]

Where is the info on the mass of the MicroSats coming from?

From the FCC filing, Purpose of Experiment

The primary structure for the Microsat-2a and -2b test spacecraft will be a box design measuring 1.1m x 0.7m x 0.7m and carries the spacecraft flight computer, power system components, attitude determination and control components, propulsion components, GPS receiver, and broadband, telemetry, and command receivers and transmitters. The primary bus is mounted on the payload truss system, which also carries communications panels, inter-satellite optical link transmitters and receivers, star trackers, and a telemetry antenna. There are two 2x8 meter solar panels. Each demonstration spacecraft has a total mass of approximately 400kg

This extract from the FCC licence for the whole constellation gave the mass for the whole starlink sat as 386kg.
Similarly, the solar panels were 2*6*2m, which has grown as well.

This sounds less like a early test satellite, and more like a full-up prototype, which has grown a little from early estimates..

The box dimensions of '1.1x0.7x0.7' are interesting.

[russianhalo117]

So why is a 400kg satellite called a microsat? How would you describe a cubesat? How big does a satellite have to be to be described as small, medium and large?

cubesats are "nanosats". Dunno if there are official weight classes, but 400kg is basically never a primary payload, so microsat seems legit.

There are 2 international forms of spacecraft classes: Lettered (like car class) and Kilogram(10, 20 50, 100, 200, 400, 800 et cetera.).

Examples of Lettered class (Lettered classes use the International English Alphabet):
S Class - Microsat (https://www.yorkspacesystems.com/?page_id=30)
U Class - Cubesat (https://en.wikipedia.org/wiki/CubeSat)

International standard sat class by kg (each kilogram class may contain more than one lettered class (sometimes referred as subclass)) are:

Large satellite (>1000kg)
Medium satellite (500-1000kg)(Macrosatellite)
Minisatellite (100–500 kg)
Microsatellite (10–100 kg)
Nanosatellite (1–10 kg)
Picosatellite (0.1–1 kg)
Femtosatellite (0.01–0.1 kg)

NASA classes small spacecraft differently than the international standards.
NASA defines small spacecraft class as:
<1kg: Femtosatellite and Picosatellite
1-10kg: Nanosatellite (Cubesat)
10-100kg: Microsatellite
100-180kg: Minisatellite
>180kg is considered by NASA to be the starting point for Macrosatellite (medium) class.

Source of my information is via the attached PDF.

[wannamoonbase]

2 per month for first half of 2018 and 3 per month for remainder gets to 30 launches. 
Just about right.  (But we can still want more...)

Agreed.

If they managed 24 over the calendar year that would be a big accomplishment.  Highest launch rate, first FH, Fairing 2, Block 5, Dragon 2.

That's a lot of work.

Until and unless they start flying Starlink flights the current market seems to support around 24 launches a year.

Right now lets get PAZ going and see how this fairing works out.

Edit: I'm looking forward to the time they add  'Experimental Fairing Recovery' footage to the webcasts.

[AncientU]

Where is the info on the mass of the MicroSats coming from?

From the FCC filing, Purpose of Experiment

The primary structure for the Microsat-2a and -2b test spacecraft will be a box design measuring 1.1m x 0.7m x 0.7m and carries the spacecraft flight computer, power system components, attitude determination and control components, propulsion components, GPS receiver, and broadband, telemetry, and command receivers and transmitters. The primary bus is mounted on the payload truss system, which also carries communications panels, inter-satellite optical link transmitters and receivers, star trackers, and a telemetry antenna. There are two 2x8 meter solar panels. Each demonstration spacecraft has a total mass of approximately 400kg

This extract from the FCC licence for the whole constellation gave the mass for the whole starlink sat as 386kg.
Similarly, the solar panels were 2*6*2m, which has grown as well.

This sounds less like a early test satellite, and more like a full-up prototype, which has grown a little from early estimates..

The box dimensions of '1.1x0.7x0.7' are interesting.

We'll be seeing lots of iterations on Starlink hardware (and software even more).
First iteration before first test sats launched is confirmation.

[deruch]

Where is the info on the mass of the MicroSats coming from?  I think we've only seen info on what was planned for the SpaceX constellation and comments that these would be prototype vehicles for testing purposes.  But nothing that they would be of such high fidelity to be close to the mass of the actual constellation sats.  Just that they would be able to test the required hardware.  I guess I had been envisioning something closer to 50-100kg max.  And very possibly smaller.

The Microsat 1a/1b sats that they didn't end up launching were along the lines of what you're envisioning.  They were very simple, no propulsion, just testing some subsystems.  The Microsat 2a/2b sats are much more functional.

Ahh.  Yep.  That was the basis of my recollection.  I didn't realize that the Microsat-2 series was significantly different from a bus perspective.  Thank you.

Thanks Gunter, too.  That was totally definitive.

[deruch]

This extract from the FCC licence for the whole constellation gave the mass for the whole starlink sat as 386kg.
Similarly, the solar panels were 2*6*2m, which has grown as well.

This sounds less like a early test satellite, and more like a full-up prototype, which has grown a little from early estimates..

The box dimensions of '1.1x0.7x0.7' are interesting.

Or that for the initial testing they aren't trying to cut down to final flight size/mass.  Though, I do think it likely that the service sats will be larger than their original filing posited.  So, maybe these are pretty close.