Asteroid 99942 · ESA Ramses escort mission

Apophis Tracker

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until closest approach on Friday, April 13, 2029, when Apophis passes about 31,600 km above Earth with ESA's Ramses spacecraft riding alongside.

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Sun Venus Earth Apophis Ramses

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Apophis from Earth——
Ramses from Earth——
Ramses to Apophis——
Signal delay to Ramses—one-way, light speed
Speed around Sun——
Speed vs Earth——

Flyby in 3D

April 13, 2029, in Earth's neighborhood. Earth turns at its real rate and is lit by the Sun for that moment. Apophis threads between the geostationary belt and the GPS satellites.

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Apophis (enlarged) Ramses Geostationary belt GPS Low orbit and ISS

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Height above Earth——
Speed vs Earth——
Directly over—latitude, longitude
Vs. geostationary belt—35,786 km up

Satellite positions are representative: the real geostationary belt holds about 550 active satellites, GPS has 31, and thousands more fly in low orbit. Apophis and Ramses are drawn much larger than life so you can see them; at true scale Apophis would be smaller than a pixel.

Spec sheet

~370 m acrossElongated, about 450 × 170 m, possibly two lobes stuck together. About as long as the Empire State Building is tall.
~6 × 10¹⁰ kgAbout 61 billion kg (estimates range 40–79 billion), roughly 600 aircraft carriers' worth of rock.
Stony, Sq-typeSurface matches LL chondrite meteorites: silicate rock rich in olivine and pyroxene, with little iron-nickel metal.
2.6–3.2 g/cm³Density similar to ordinary rock; it may be a rubble pile rather than one solid block.
30.7 km/s around the SunAbout 110,000 km/h on average. At the 2029 flyby it moves 7.4 km/s relative to Earth (about 26,600 km/h).
Tumbles every ~30.6 hIt doesn't spin cleanly on one axis; it wobbles, which the flyby is expected to change.
Albedo 0.35Reflects about a third of the sunlight that hits it, brighter than most asteroids.
Orbit: 323.6 daysSwings from 0.75 to 1.10 AU from the Sun, tilted 3.3° to Earth's orbit. Widens to about 1.1 AU average after 2029.

Gallery

RamsesTap the caption to view
Ramses powered on for the first time
Ramses powered on for the first timeSep 2026 · ESA
Core moduleTap the caption to view
Ramses core module in the cleanroom
Ramses core module in the cleanroomSep 2026 · ESA
At ApophisTap the caption to view
Artist's view: Ramses at Apophis
Artist's view: Ramses at ApophisIllustration · ESA
FlybyTap the caption to view
Apophis passes Earth on Friday 13 April 2029
Apophis passes Earth on Friday 13 April 2029Illustration · ESA
RadarTap the caption to view
Real radar images of Apophis, March 2021, 17 million km away
Real radar images of Apophis, March 2021, 17 million km awayNASA/JPL-Caltech and NSF/AUI/GBO
JAXATap the caption to view
Japan's contributions to Ramses
Japan's contributions to RamsesJun 2026 · ESA / JAXA

Images from ESA and NASA. Swipe on a phone; tap a caption for the full image and story.

Latest news

Updated Oct 26, 2026

Forbes

In 900 days, Apophis will come closer than some satellites

Viewing outlook for April 2029, and ESA's proposed LUMIO cubesat that could watch the flyby from beyond the Moon.
ESA

First switch-on for the ESA-JAXA Ramses spacecraft

Prime contractor OHB powered Ramses on for the first time, a key step toward a spring 2028 launch.
OHB

OHB begins building Ramses in Bremen

Assembly started in OHB's cleanroom, reusing design heritage from ESA's Hera asteroid mission.
Phys.org

ESA and JAXA sign agreement for Ramses

The two agencies formalized their joint role in the mission on May 7, 2026.
OHB

OHB wins €81 million contract to build Ramses

Contract covers construction, assembly and testing of the spacecraft.
ESA

ESA awards contracts for Ramses mission to Apophis

Spacecraft and cubesat contracts signed, starting full development.

Mission clock

Distance from Earth

Orange is Apophis, lavender is Ramses. After the flyby, Earth's pull stretches Apophis into a wider orbit, so the swings change rhythm.

The 2029 flyby, to scale

21:46 UTC · Apr 13, 2029Closest approach
38,017 kmfrom Earth's center (±3.4 km)
Magnitude 3.1naked-eye visible from dark skies
0.92 → 1.1 AUEarth's pull flips its orbit from Aten to Apollo class