Author Topic: Sputnik 3  (Read 772 times)

Offline RIB

  • Member
  • Posts: 32
  • USA
  • Liked: 5
  • Likes Given: 52
Sputnik 3
« on: 10/05/2017 09:26 PM »
Sputnik 3 had an announced weight weight of 2926 lbs and an orbit of 135 miles by 1158 miles . How much payload could an R-7 similar to Sputnik's 3 launch vehicle put into a 115 by 115 mile orbit with a 65.18 degree inclination?

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8506
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1022
  • Likes Given: 234
Re: Sputnik 3
« Reply #1 on: 10/06/2017 12:34 AM »
You are assuming it could, did the R-7 have the restart (and guidance) capability to place something in a circular orbit?
If you're happy and you know it,
It's your med's!

Offline RIB

  • Member
  • Posts: 32
  • USA
  • Liked: 5
  • Likes Given: 52
Re: Sputnik 3
« Reply #2 on: 10/06/2017 04:15 AM »
Hypothetically..........

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8506
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1022
  • Likes Given: 234
Re: Sputnik 3
« Reply #3 on: 10/06/2017 02:05 PM »
If it didn't have a restart capability, it might not have been able to.

Speaking of which, has anyone ever model'd Sputnik 3's launch profile? It's not in John Schilling's launch vehicle calculator. http://silverbirdastronautics.com/LVperform.html
If you're happy and you know it,
It's your med's!

Offline kevin-rf

  • Elite Veteran
  • Senior Member
  • *****
  • Posts: 8506
  • Overlooking the path Mary's little Lamb took..
  • Liked: 1022
  • Likes Given: 234
Re: Sputnik 3
« Reply #4 on: 10/06/2017 02:18 PM »
Btw. Best I could come up with using the wiki values for Vostok sans the upper stage. (Vostok was an R-7 with an upper stage).

Feel free to improve on the model... Without a restartable upper stage, the vehicle is quite limited in what it can place in orbit. 
If you're happy and you know it,
It's your med's!

Offline Alter Sachse

  • Full Member
  • ****
  • Posts: 424
  • Germany (near Heidelberg)
  • Liked: 63
  • Likes Given: 101
Re: Sputnik 3
« Reply #5 on: 10/06/2017 04:15 PM »
With a similar version the "Korabl" spaceships were launched into a low orbit. Weight approx. 4600 kg.

Offline RIB

  • Member
  • Posts: 32
  • USA
  • Liked: 5
  • Likes Given: 52
Re: Sputnik 3
« Reply #6 on: 10/06/2017 05:38 PM »
See I've always wondered about the Sputnik launch vehicle because Sputnik 3 was much heavier than 1 & 2 yet, had a higher apogee, thus, a higher burnout velocity.

Offline Patchouli

  • Senior Member
  • *****
  • Posts: 4201
  • Liked: 118
  • Likes Given: 210
Re: Sputnik 3
« Reply #7 on: 10/06/2017 06:43 PM »
Btw. Best I could come up with using the wiki values for Vostok sans the upper stage. (Vostok was an R-7 with an upper stage).

Feel free to improve on the model... Without a restartable upper stage, the vehicle is quite limited in what it can place in orbit. 
I wonder could they have used just the thrust from gas generator to the turbo pumps to  circularize the orbit.
These ran on H2O2 so they could be turned on and off by not much more than turning a valve though a free running turbo pump tends to over speed with catastrophic results.

One thing I find interesting work began on Sputnik 3 before Sputnik 1 and 2 so the booster was built for the heavier payload.



Offline douglas100

  • Senior Member
  • *****
  • Posts: 2150
  • Liked: 214
  • Likes Given: 95
Re: Sputnik 3
« Reply #8 on: 10/06/2017 07:08 PM »
Bear in mind the R-7 was an ICBM. Restarting the central core was never something that was required (and the R-7 never had a restartable upper stage until Fregat.) The vehicle could have flown the payload into a lower circular orbit with a single burn of the central core if the guidance had been up to it.

What became Sputnik 3 was originally planned as the USSR's contribution to the International Geophysical Year. It got delayed and Korolov got permission to launch a simple satellite first. The rest is history.
Douglas Clark

Offline WallE

  • Full Member
  • *
  • Posts: 155
  • Liked: 25
  • Likes Given: 0
Re: Sputnik 3
« Reply #9 on: 10/08/2017 11:53 PM »
The R-7 was way oversized for an ICBM because mid-1950s Soviet warheads were larger than American ones due to their less advanced manufacturing capabilities. This problem was however resolved by the end of the decade so the R-7 in practice was already obsolete by the time it reached operational status. Korolev knew it was useless as a practical ICBM, but more than suitable for space launches (what he really cared about anyway) and in the meantime it satisfied the demands of the Soviet military for a long-range ballistic missile.

As I'd mentioned before, the largely unproven booster performed well on Sputnik 1-2 but as they kept making modifications/enhancements to the R-7, trouble started to crop up. The first attempt at launching a Sputnik 3 satellite on 4/27/58 failed when high vibration levels caused the strap-ons to break off about 90 seconds into launch. The booster crashed downrange and recovery crews located the impact site and the banged-up, but mostly intact satellite. It looked ok at first, but the internals caught fire from an electrical short after being returned to Baikonur.

Sputnik 3 was launched successfully on May 15, the first anniversary of the R-7's maiden flight. In order to work around the vibration issue, they throttled down the strap-on engines at T+85 seconds, the point where trouble started to occur on the earlier launch. It worked but vibration levels were still dangerously high. The problem had mainly to do with some weight-saving measures on the latest R-7 vehicles including lighter-weight slosh baffles in the propellant tanks and it ended up plaguing lunar probe shots later in 1958.

The R-7's throttleable engines were admittedly a capability American LVs lacked; until the Shuttle program, all American LVs used fixed-thrust engines for the main stage portion of launch.

Tags: