Position & trajectory
On the way to L2
Roman is coasting to the second Sun–Earth Lagrange point, 1.50M km beyond Earth on the side facing away from the Sun. There is no engine burning for most of the trip: the launch vehicle did nearly all the work, and the observatory simply falls outward, slowing the whole way, until a small burn at the far end drops it into a halo orbit around a point in empty space.
Trajectory
Sun–Earth rotating frame
State vector
Modeled from the published flight plan
Values are propagated analytically from the published flight plan — a radial two-body coast matched to the planned insertion epoch, then a halo orbit about L2. They are not a live telemetry feed, and will drift from the real trajectory by however much the actual correction burns differ from plan.
Range from Earth
The coast is ballistic. Speed falls the whole way out — the observatory arrives at L2 moving slower than a passenger jet.
Burn schedule
A trans-L2 injection is deliberately aimed a little short. The observatory can add velocity but never subtract it — turning around to brake would point the sunshade the wrong way and bake the optics — so an under-burn is correctable and an over-burn is not. The model here flies that shape: injection falls inside L2, and TCM-1 supplies the difference.
L+2 days
plannedTrajectory Correction 1
31 Aug 2026
Δv 28.8 m/smodeled
The first and largest correction burn removes launch-vehicle injection error. It must fire early — a trans-L2 trajectory is deliberately biased short so it can never be aimed at the observatory's own sunshade.
L+18 days
plannedTrajectory Correction 2
17 Sept 2026
A small mid-course cleanup burn refines the approach so that the insertion maneuver at L2 stays inside its propellant budget.
L+30 days
plannedL2 Orbit Insertion
29 Sept 2026
A modest burn at the edge of the Earth–Sun L2 region captures the observatory into a wide halo orbit roughly 1.5 million km from Earth. The halo is unstable by design, so it is maintained with small station-keeping burns every few weeks.
Nothing on this page is a live feed. Range, speed and position are propagated from the published flight plan; the real trajectory will differ by however much the actual correction burns differ from plan. Once Roman is being tracked, JPL Horizons will publish a real ephemeris — the model here sits behind a single function so it can be replaced by one.