Soyuz & ISS

Quick Facts: ISS

• Mass: 455 t

• Orbit: ~400 km near-circular LEO, 51.6° Inclination

• PV-Area: ~4500 m²

• Zarya was launched in 1998

• Since 2000

(Z-Axis is Nadir)

Quick Facts: Soyuz

• Maidenflight: 1966 (uncrewed), 1967 (crewed)

• Crew: 3

• Δv: 390 m/s (Soyuz-TMA)

• Propellants: N2O4 / UDMH (He pressurized)

• Cabin Atmosphere:

  • 20% O2, 80% N2

  • 1.01 bar (nominal), 0.6-1.3 bar range

Rendezvous

• The targeted approach of two objects in space

• Orbital mechanics must be taken into account!

• Distance to ISS > 1000m

Docking

• The connection between two spaceships

• Orbital mechanics can be (mostly) neglected

• Distance to ISS < 1000m

Berthing

• Berthing refers to mating operations where a passive module/vehicle is placed into the mating interface of another space vehicle by using a robotic arm

Hohmann transfer

Sokol (russian for falcon)

• Propulsion System

  • Helium System

  • Propellant System

  • Thruster Groups

  • Main Engine

• Energy System / Solar Cell Deployment

• Lighting

192km to 200km

(Namen der Orbits, Namen der Transfers, Anzahl der Orbits für entsprechende)

To provide pure oxigen for pre-breathing for the astronauts to purge nitrogen from their system. This is necessary, because the Sokol suits will only maintain ~400 hPa of pressure in case of loss of pressure in the cabin, to prevent the suit from becoming too stiff. Without pre-breathing, this could lead to decompression sickness.

Safety zone to protect the ISS and the spacecraft.

Sphere around the ISS (CoG?) with radius of 200m.

Only allowed to enter through approach corridors.

Prior safety check necessary before entry.

Speed limits for spacecraft (keep exhaust emissions low).

Rotation:

• attitude changes, position (center of gravity) stays the same

Translation:

• Position (center of gravity) changes, attitude stays the same

• never lose sight

• never leave the approach corridor

Automatic and manual

Because there is no window (=> no line of sight) at the center of the docking port. The periscope’s end is off-center, so the docking marker has to be off-center as well.

• parachutes

• retro rockets

• seat

• 51.6° inclination

• orbital period of approx. 90 minutes

• altitude approx. 400km above Earth’s surface

• identical orbital plane of both spacecraft

  • inclination

  • right ascension of the ascending node (ascending node through orbital insertion)

• congruent orbital ellipses

• temporal synchronization

7m long and 2.7m in diameter

310t

Orbital module, Descent module, Service Module

• Keep - Out – Sphere: (r = 200 m) may only be entered via approach corridors

• Observe the (speed) restrictions!

All flight maneuvers from orbit insertion to 1000m proximity to the ISS, Orbital mechanics relevant!

All flight maneuvers in the 1000m range from the ISS to the docking port, Orbital mechanics are negligible!

• Phasing/Rendezvous

• Fly-Around

• Docking

• “Never change a running system” & use lessons learned from previous problems

• Derived from Vostok and Voshkod capsules, improved since 1967

• Structure and Mechanisms Subsystem (SMS)

• Attitude & Orbit Control Subsystem (AOCS)

• Propulsion Subsystem (PS)

• Communication Subsystem (CS)

• Command and Data Handling Subsystem (C&DH)

• Electrical Power Subsystem (EPS)

• Thermal Control Subsystem (TCS)

• Environmental Control and Life Support System (ECLSS)

• Extra Vehicular Activity Systems (EVA) – better: “itself a spacecraft”

• Different control loops for orbital flight vs. Descent & Re-Entry: Digital Loop, Analog Loop

• 12 x DPO-B thrusters for docking & attitude control (& 4 x DPO-BT reserve thrusters if Main SKD Engine failure during de-orbit)

• 12 x DPO-M thrusters for attitude control

• Integrated power supply

  • Power generated by Solar Arrays

  • Power stored in rechargeable batteries (& backup battery)

• Autonomous chemical batteries for emergencies

• Passive and Active thermal control

• 4 active thermal control loops:

  • Internal Thermal Loop

  • External Thermal Loop

  • Condensate Evacuation Loop

  • Water Cooling Loop

• TCS contains:

  • Heat Exchangers

  • Fans

  • Pumps

  • Heaters

  • Cooling/Drying Unit

  • Radiator

• Oxygen is stored in tanks and pumped into DM & OM

• Carbon Dioxide is removed by Lithium Hydroxide canisters

• Small Oxygen Tank used during descent, emergency regenerator if DM can not be opened

• Dehumidification with Condensing Heat Exchangers (“Cooling/Drying Units”)

• mission objectives

  • tech demo, science, exploration, lunar landing, …

• intended use

  • crew transfer, “space lorry”, science lab

• technological advancements

  • reusability, controllability, …

• key players/funding

  • governments/state agencies vs. private companies/investors

• national priority: e.g. space race

• mission duration

• crew size

• mass

• End of the Shuttle program 2011

• US paid a lot for seats on the Soyuz

• US access to space should be ensured

• Diverse approaches possible

• Modularity

• Reusability

• Escape System integrated into Crew Module, instead of historic launch escape towers

• Landing & Parachutes (What do you mean?)

• More deep-space capabilities (increased radiation shielding, longer mission durations)

• former spacecraft:

  • Vostok, Mercury, Voskhod, Gemini, Apollo, Space Shuttle

• Operational spacecraft:

  • Soyuz, Shenzhou, Crew Dragon, (Starliner)

• Future spacecraft:

  • Orion (maybe active already?), Starship, Gaganyaan, Mengzhou, Orel

1. identical orbital plane of both s/c

   • inclination

   • right ascension of the ascending node -> through orbit insertion

2. congruent orbital ellipses

   • Hohmann transfer

3. temporal synchronization

   • temporal orbit change

1. 2 Orbits in the Insertion-Orbit

2. Hohmann-Transfer to Phasing Orbit

3. 30.5 Orbits in Phasing Orbit

4. Bi-Elliptical Transfer to ISS

Similarities:

• automated redezvous & docking:

  • most modern s/c (Soyuz, Starliner, Crew Dragon, Orion, Shenzhou) use automated systems for Rendezvous and Docking

  • manual override as backup

• Phasing orbits:

  • series of orbital maneuvers to match the target’s orbit

• Crew safety:

  • abort capabilities and redundant systems during launch and docking

    • different abort mechanisms

Differences:

• manual vs. automated docking:

  • Space Shuttle relied on manual control for final approach and docking

  • current capsules use automation with crew as backup

• launch profiles:

  • Starliner and Shuttle use a suborbital insertion followed by an onboard burn for orbit insertion

  • Soyuz and Crew Dragon insert directly into orbit

• Docking Hardware:

  • different docking mechanisms: probe-and-drogue, NASA docking system, androgynous systems

  • affects compatibility, rescue possibilities and approach procedures

• Approach Geometry:

  • Shuttle approached along the R-bar

  • Modern capsules use automated approach corridors optimized for their specific docking systems

• Mission Duration to Docking:

  • Soyuz and Shenzhou can use either fast (6-hour) or standard (2-day) redezvous

  • Crew Dragon and Starliner typically dock within 24-27 hours

  • Shuttle often took 2 days

• Lift off

• 41.5km: 1st stage separation

• 85km: escape tower & launch shroud jettison

• 176km: 2nd stage separation & 3rd stage ignition

• 208km: 3rd stage cut-off & Soyuz separation