TBOP001
International Space Station interception
***COMPLETED***
Departure: Earth, Cape Canaveral.
Vehicle: Delta Glider
Phase one
(low orbit launch)
The ship was launched to an orbit with an
apoapsis at 250 km and a periapsis at 220 km. The altitude for the periapsis
of 220 km was chosen as a safe altitude to allow for the deformation of
the orbit due gravity gradients.
Phase two
(orbit alignment)
The ship's orbit was aligned with the ISS's with
a difference in inclinations of 1.56 degrees. This was achieved in one
burn at the Ascending Node.
Phase three
(orbit synchronization)
The ship's apoapsis was extended to intercept
the ISS's orbit; this allowed us to use the Orbit Synchronization Multi-Function-Display.
The periapsis was left at an altitude of 220 km in order to have the closing
velocity desired. Several burns were needed to maintain the orbit
stable, as it was affected by the moon's gravity, and other gradients.
Phase four
(pre-appoach)
This started when a relative longitude of 10 degrees was achieved. Adjustments to the orbit were made so that the apopasis and periapsis coincided. The ship's periapsis was placed at 6.691M (relative to the ISS's Pe at 6.691M) and the apoapsis at 6.739M (relative to the ISS's Ap at 6.819M). The difference in apopasis was maintained so an acceptable closure could be achieved.
Phase five
(approach/dock)
Approach procedures began at about 100K from the ISS (0.06 RLong).
Permission was requested for docking, and Docking Port One was cleared. Random burns were made to approach the ISS up to a distance to 13K. At this distance, the ship was oriented towards the velocity indicator and burns were made to achieve a closing velocity of 0. Once this was done, burns directed towards the approach patch were made. When the ship was located on the approach path, engines were switched to linear mode, to allow for docking adjustments. Everything was aligned and in place well before the middle of the approach path; closing velocity was reduced as the distance to the ISS decreased. The docking took place with a CVel of 0.05, and 42.3% fuel left.