juliensimon/solar-orbiter-encounters

Solar Orbiter Encounter Timeline

Credit: NASA/SDO

Part of a dataset collection on Hugging Face.

Dataset description

Complete mission event timeline for the ESA/NASA Solar Orbiter — the first spacecraft designed to deliver sustained close-up views of the Sun's polar regions. Compiled from ESA Solar Orbiter operations documents and the Mueller et al. 2020 mission overview paper (A&A 642, A1).

The dataset covers all perihelion encounters from P1 (2020-06-15, 0.516 AU) through the planned encounters of the early high-inclination phase, interleaved with the gravity assists (5 Venus + 1 Earth) that progressively raised orbital inclination above the ecliptic. Each row records the event date and time in UTC, perihelion distance in AU, R_sun, and million km, aphelion distance, the heliographic latitude reached on each orbit, flyby altitudes, and the mission phase identifier.

Solar Orbiter's distinctive trajectory complements NASA's Parker Solar Probe: PSP achieves the closest physical approach (9.86 R_sun) but stays near the ecliptic, while Solar Orbiter's nominal perihelion of 0.293 AU (63 R_sun) is paired with a planned ramp to ~33 degrees heliographic latitude, enabling the first systematic remote-sensing observations of the solar poles. Use this dataset alongside juliensimon/parker-solar-probe-encounters for direct mission comparison, with juliensimon/sunspot and juliensimon/solar-flares for solar-activity context, and with juliensimon/donki for cross-correlation against catalogued space weather events.

This dataset is suitable for tabular classification, time-series forecasting tasks.

Schema

Column	Type	Description	Sample	Null %
event_type	str	Event category: 'perihelion' for the spacecraft's closest-Sun point on each orbit, 'venus_flyby' for a Venus gravity assist, 'earth_flyby' for the single Earth gravity assist on 2021-11-27	perihelion	0.0%
sequence_number	int64	Perihelion number for perihelion events (1-13+) or flyby number within its body for gravity assists (Venus 1-5+, Earth 1)	1	0.0%
event_label	str	Human-readable label such as 'P5' for perihelion 5, 'VGA-4' for Venus gravity assist 4, or 'EGA-1' for the Earth gravity assist	P1	0.0%
event_datetime_utc	datetime64[us]	Event date and time in UTC (perihelion epoch for perihelion events, closest-approach time for flybys); minute-precision values are taken from ESA mission planning publications	2020-06-15 17:32:00	0.0%
event_year	int64	Calendar year of the event (integer, derived from event_datetime_utc)	2020	0.0%
perihelion_distance_au	float64	Heliocentric distance at perihelion in astronomical units (1 AU = 149,597,870.7 km); null for flybys; the operational orbit perihelion is ~0.293 AU	0.516	31.6%
perihelion_distance_million_km	float64	Heliocentric distance at perihelion in millions of kilometers; null for flybys; operational perihelion ~43.8 million km	77.1925012812	31.6%
perihelion_distance_rsun	float64	Heliocentric distance at perihelion in solar radii (R_sun = 695,700 km); null for flybys; operational perihelion ~63 R_sun (compare to Parker Solar Probe at 9.86 R_sun for the closest approach)	110.95659232600258	31.6%
aphelion_distance_au	float64	Heliocentric distance at the corresponding aphelion in astronomical units; null for flybys; operational aphelion ~0.92 AU	0.916	31.6%
heliographic_latitude_deg	float64	Maximum heliographic latitude of the spacecraft on the orbit hosting this perihelion, in degrees; positive = north of the solar equator; rises from ~5-6 deg in the Cruise phase to 17+ deg after VGA-4 and 24+ deg after VGA-5	5.6	31.6%
flyby_body	str	For gravity assists, the body providing the assist: 'Venus' or 'Earth'; null for perihelion events	Venus	68.4%
flyby_altitude_km	float64	Closest-approach altitude above the body's mean surface in kilometers for gravity assists; null for perihelion events; ranges from 379 km (VGA-4, lowest Venus altitude) up to ~7,995 km (VGA-2)	7500.0	68.4%
inclination_after_deg	float64	Heliographic-equator orbital inclination achieved after this gravity assist, in degrees; null for events that did not change orbit inclination	17.0	89.5%
mission_phase	str	Mission phase identifier: Cruise (pre-2022, before nominal orbit), Nominal (nominal science orbit ~0.29 AU perihelion in the ecliptic), High-Lat (high-inclination phase after VGA-4, sustained polar views of the Sun); null for flyby rows	Cruise	31.6%
notes	str	Brief free-text annotation describing significance of the event (e.g. 'began high-inclination phase'); short for perihelion rows, longer for flyby rows	First Venus flyby; ecliptic	68.4%

Quick stats

• 13 perihelion encounters (P1 through P13) plus 5 Venus gravity assists and 1 Earth gravity assist across 6 years of operations
• Closest perihelion: 0.293 AU (63.0 R_sun, ~43.8 million km) — operational orbit since 2022
• Maximum heliographic latitude: 17 deg after VGA-4 (Feb 2025), ramping toward ~33 deg over subsequent Venus flybys for sustained polar views of the Sun
• Lowest Venus flyby altitude: 379 km (VGA-4, Feb 2025) — placed spacecraft into the high-inclination phase
• Mission phases: Cruise (pre-2022), Nominal (2022-2024 ecliptic science orbit), High-Lat (post-VGA-4 polar campaign)

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/solar-orbiter-encounters", split="train")
df = ds.to_pandas()

from datasets import load_dataset
import matplotlib.pyplot as plt

so = load_dataset("juliensimon/solar-orbiter-encounters", split="train").to_pandas()
psp = load_dataset("juliensimon/parker-solar-probe-encounters", split="train").to_pandas()

# Compare Sun-approach distance (R_sun) for the two heliospheric flagships
peri_so = so[so["event_type"] == "perihelion"]
peri_psp = psp[psp["event_type"] == "perihelion"]

fig, ax = plt.subplots(figsize=(12, 5))
ax.scatter(peri_so["event_datetime_utc"], peri_so["perihelion_distance_rsun"],
           label="Solar Orbiter", s=60)
ax.scatter(peri_psp["event_datetime_utc"], peri_psp["perihelion_distance_rsun"],
           label="Parker Solar Probe", s=60)
ax.set_yscale("log")
ax.invert_yaxis()
ax.set_ylabel("Perihelion distance (R_sun, log scale)")
ax.set_title("Heliospheric flagships: PSP gets closest, Solar Orbiter goes polar")
ax.legend()
plt.tight_layout()
plt.show()

# Show how heliographic latitude ramps after each Venus flyby
print(peri_so[["event_label", "event_datetime_utc",
               "perihelion_distance_au", "heliographic_latitude_deg",
               "mission_phase"]].to_string(index=False))

Data source

https://www.esa.int/Science_Exploration/Space_Science/Solar_Orbiter

Related datasets

• juliensimon/parker-solar-probe-encounters

• juliensimon/sunspot

• juliensimon/solar-flares

• juliensimon/donki

• juliensimon/solar-wind

• juliensimon/space-weather

If you find this dataset useful, please consider giving it a like on Hugging Face. It helps others discover it.

About the author

Created by Julien Simon — AI Operating Partner at Fortino Capital. Part of the Space Datasets collection.

Citation

@dataset{solar_orbiter_encounters,
  title = {Solar Orbiter Encounter Timeline},
  author = {juliensimon},
  year = {2026},
  url = {https://huggingface.co/datasets/juliensimon/solar-orbiter-encounters},
  publisher = {Hugging Face}
}

License

CC-BY-4.0